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, Available online ,
doi: 10.14133/j.cnki.1008-9357.20200228001
Abstract:
Firstly, Fe3O4 nanospheres were prepared by solvothermal method, which were used as magnetic cores and coated with chitosan (CS) crosslinked by glutaraldehyde. Then, polyoxometalates (POMs) were supported onto the magnetic chitosan carriers by electrostatic bonding and three magnetic polyoxometalates microspheres (Fe3O4@CS@POM) were prepared, including Keggin type magnetic phosphotungstic acid (Fe3O4@CS@PW12) and Dawson type magnetic phosphotungstic acid (Fe3O4@CS@P2W17 and Fe3O4@CS@P2W18). Their structures and morphologies were characterized by FT-IR、UV-Vis、EA and TEM. The catalytic activity of Fe3O4@CS@POM on tetrahydrothiophene (THT) was investigated in detail. It is shown that all the three kinds of Fe3O4@CS@POM microspheres have good catalytic oxidation abilities to THT, among which Fe3O4@CS@PW12 shows the best catalytic activity. The conversion of THT could reach 100 % at room temperature after 105 min with a small amount of Fe3O4@CS@PW12 (0.01 g). The catalytic oxidation process follows the quasi-first order kinetic model. The catalyst could be separated quickly and efficiently in the external magnetic field. In addition, Fe3O4@CS@PW12 has good reusability, and the catalytic activity remains stable after 5 cycles.
Firstly, Fe3O4 nanospheres were prepared by solvothermal method, which were used as magnetic cores and coated with chitosan (CS) crosslinked by glutaraldehyde. Then, polyoxometalates (POMs) were supported onto the magnetic chitosan carriers by electrostatic bonding and three magnetic polyoxometalates microspheres (Fe3O4@CS@POM) were prepared, including Keggin type magnetic phosphotungstic acid (Fe3O4@CS@PW12) and Dawson type magnetic phosphotungstic acid (Fe3O4@CS@P2W17 and Fe3O4@CS@P2W18). Their structures and morphologies were characterized by FT-IR、UV-Vis、EA and TEM. The catalytic activity of Fe3O4@CS@POM on tetrahydrothiophene (THT) was investigated in detail. It is shown that all the three kinds of Fe3O4@CS@POM microspheres have good catalytic oxidation abilities to THT, among which Fe3O4@CS@PW12 shows the best catalytic activity. The conversion of THT could reach 100 % at room temperature after 105 min with a small amount of Fe3O4@CS@PW12 (0.01 g). The catalytic oxidation process follows the quasi-first order kinetic model. The catalyst could be separated quickly and efficiently in the external magnetic field. In addition, Fe3O4@CS@PW12 has good reusability, and the catalytic activity remains stable after 5 cycles.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20200116001
Abstract:
In order to achieve high efficiency in the cycloaddition reaction of CO2 under the conditions of mild environment and absence of cocatalyst, two kinds of porphyrin-based porous organic polymers (PPOP-COOH and PPOP-I) were designed and synthesized in this paper. The nucleophilic groups and metal active centers of quaternary ammonium salts were introduced into the polymers by means of pre-modification and post-modification. The two crosslinked polymers showed excellent chemical and thermal stability. The chemical structures and pore structures of the two polymers were characterized, and both of them had hierarchical porous structure with specific surface areas of 302～514 m2/g. Under the condition of 298 K, CO2 adsorption and desorption tests were carried out, and the results showed that CO2 adsorption capacity of carboxyl-containing polymer was greater than that of quaternary ammonium salt containing polymer. The effect of the catalyst on the cycloaddition reaction of CO2 was studied. The results showed that the synergistic effect of Lewis acid metal ions, nucleophiles and multi pore structure greatly promoted the CO2 cycloaddition reaction. It is important to note that although containing quaternary ammonium salt ions than CO2 adsorption capacity of polymer containing carboxyl polymer, but its catalytic performance is far higher than that of polymer containing carboxyl. Under moderate conditions (80 ℃, 0.3 MPa, 24 h), the reaction selectivity and conversion can reach higher than 99%, and still presented good catalytic performances after repeated use for many times.
In order to achieve high efficiency in the cycloaddition reaction of CO2 under the conditions of mild environment and absence of cocatalyst, two kinds of porphyrin-based porous organic polymers (PPOP-COOH and PPOP-I) were designed and synthesized in this paper. The nucleophilic groups and metal active centers of quaternary ammonium salts were introduced into the polymers by means of pre-modification and post-modification. The two crosslinked polymers showed excellent chemical and thermal stability. The chemical structures and pore structures of the two polymers were characterized, and both of them had hierarchical porous structure with specific surface areas of 302～514 m2/g. Under the condition of 298 K, CO2 adsorption and desorption tests were carried out, and the results showed that CO2 adsorption capacity of carboxyl-containing polymer was greater than that of quaternary ammonium salt containing polymer. The effect of the catalyst on the cycloaddition reaction of CO2 was studied. The results showed that the synergistic effect of Lewis acid metal ions, nucleophiles and multi pore structure greatly promoted the CO2 cycloaddition reaction. It is important to note that although containing quaternary ammonium salt ions than CO2 adsorption capacity of polymer containing carboxyl polymer, but its catalytic performance is far higher than that of polymer containing carboxyl. Under moderate conditions (80 ℃, 0.3 MPa, 24 h), the reaction selectivity and conversion can reach higher than 99%, and still presented good catalytic performances after repeated use for many times.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20200103001
Abstract:
In this paper, raspberry-like polydopamine/copper nanoparticles (PDA-Cu NPs) were constructed by simply adjusting the contents of copper source and reduction temperature owing to the good adhesion properties of polydopamine (PDA) with metal particles. The successful introduction of copper nanoparticles were confirmed by X-ray diffractomete (XRD), Zeta potential. Scanning electron microscopy (SEM) results showed that the raspberry-like structure had been successfully constructed. Besides the results showed that when the reduction temperature was 60 °C, the copper nanoparticles had more uniform particle size and when the mass ratio of copper nitrate to PDA was less than 6/1, the copper nanoparticles were evenly distributed on PDA particles. The static contact angle measurements revealed that the introduction of copper nanoparticles increased the surface roughness of the PDA particles, and the surface contact angle was up to 102.2 °, showing that the modified particles turned from hydrophilic to hydrophobic. At the same time, copper nanoparticles have good antibacterial properties. The antibacterial activity of raspberry-like nanoparticles were evaluated by shake flask method. Compared with pure dopamine nanoparticles, PDA-Cu NPs had excellent antibacterial properties. With the increase of copper content, 100% sterilization can be achieved, and the antibacterial performance against S. epidermidis was better than that of E. coli. The bacterial zone experiments showed that when the mass ratio of copper nitrate to PDA was 6/1, it had clear zone of inhibition and the diameter was larger than that of 8/1, suggesting the optimal antibacterial properties. The MIC and MBC values of raspberry-like nanoparticles made from optimal reaction conditions for E. coli were 48.7 μg/mL and 195.0 μg/mL, and the MIC and MBC values for S. epidermidis were 39.0 μg/mL and 97.5 μg/mL, respectively. The raspberry-like nanoparticles showed good abtibacterial properties, which were expected to have a good application in biomedical fields.
In this paper, raspberry-like polydopamine/copper nanoparticles (PDA-Cu NPs) were constructed by simply adjusting the contents of copper source and reduction temperature owing to the good adhesion properties of polydopamine (PDA) with metal particles. The successful introduction of copper nanoparticles were confirmed by X-ray diffractomete (XRD), Zeta potential. Scanning electron microscopy (SEM) results showed that the raspberry-like structure had been successfully constructed. Besides the results showed that when the reduction temperature was 60 °C, the copper nanoparticles had more uniform particle size and when the mass ratio of copper nitrate to PDA was less than 6/1, the copper nanoparticles were evenly distributed on PDA particles. The static contact angle measurements revealed that the introduction of copper nanoparticles increased the surface roughness of the PDA particles, and the surface contact angle was up to 102.2 °, showing that the modified particles turned from hydrophilic to hydrophobic. At the same time, copper nanoparticles have good antibacterial properties. The antibacterial activity of raspberry-like nanoparticles were evaluated by shake flask method. Compared with pure dopamine nanoparticles, PDA-Cu NPs had excellent antibacterial properties. With the increase of copper content, 100% sterilization can be achieved, and the antibacterial performance against S. epidermidis was better than that of E. coli. The bacterial zone experiments showed that when the mass ratio of copper nitrate to PDA was 6/1, it had clear zone of inhibition and the diameter was larger than that of 8/1, suggesting the optimal antibacterial properties. The MIC and MBC values of raspberry-like nanoparticles made from optimal reaction conditions for E. coli were 48.7 μg/mL and 195.0 μg/mL, and the MIC and MBC values for S. epidermidis were 39.0 μg/mL and 97.5 μg/mL, respectively. The raspberry-like nanoparticles showed good abtibacterial properties, which were expected to have a good application in biomedical fields.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190512001
Abstract:
Poly(D, L-lactide) (PDLLA) with high molecular weight was prepared by ring opening polymerization (ROP) of D, L-lactide. Effects of reaction temperature, reaction time and molar ratio of catalyst to monomer on the molecular weight of PDLLA were investigated through orthogonal synthesis experiments to optimize the polymerization parameters. The number-average molecular weight, chemical structure, thermal properties and mechanical properties of the prepared PDLLA were analyzed by gel chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and universal testing instruments. The degradation properties and cytocompability against fibroblasts (L929) of PDLLA were also evaluated in vitro. The orthogonal experimental results indicated that the optimal parameters for synthesis of high molecular weight PDLLA were that with the molar ratio of catalyst to monomer of 2.04∶5 000, the reaction temperature at 135 °C, and the polymerization time for 4.5 h. Under such conditions, PDLLA with a number–average molecular weight of 2.01×105 was obtained. When the monomer conversion rate was considered in the meantime, the reaction time could be selected as 6.0 h. The obtained PDLLA had a tensile strength of (39.91±1.34) MPa, an elongation at break of 3.94%±0.54%, and an elastic modulus of (1.68±0.34) GPa. The degradation rate increased rapidly after 220 d incubation in phosphate buffer saline (PBS). The PDLLA membrane could promote the proliferation of fibroblasts in vitro, indicating its good cytobiocompatability.
Poly(D, L-lactide) (PDLLA) with high molecular weight was prepared by ring opening polymerization (ROP) of D, L-lactide. Effects of reaction temperature, reaction time and molar ratio of catalyst to monomer on the molecular weight of PDLLA were investigated through orthogonal synthesis experiments to optimize the polymerization parameters. The number-average molecular weight, chemical structure, thermal properties and mechanical properties of the prepared PDLLA were analyzed by gel chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and universal testing instruments. The degradation properties and cytocompability against fibroblasts (L929) of PDLLA were also evaluated in vitro. The orthogonal experimental results indicated that the optimal parameters for synthesis of high molecular weight PDLLA were that with the molar ratio of catalyst to monomer of 2.04∶5 000, the reaction temperature at 135 °C, and the polymerization time for 4.5 h. Under such conditions, PDLLA with a number–average molecular weight of 2.01×105 was obtained. When the monomer conversion rate was considered in the meantime, the reaction time could be selected as 6.0 h. The obtained PDLLA had a tensile strength of (39.91±1.34) MPa, an elongation at break of 3.94%±0.54%, and an elastic modulus of (1.68±0.34) GPa. The degradation rate increased rapidly after 220 d incubation in phosphate buffer saline (PBS). The PDLLA membrane could promote the proliferation of fibroblasts in vitro, indicating its good cytobiocompatability.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20200327001
Abstract:
Carbon monoxide (CO) is a gaseous transmitter that has received mounting interest because of its therapeutic potentials in the treatment of inflammation, bacterial infection, cancer and so on. However, the clinical application of CO is remarkably hindered by the difficulty in precisely controlling CO concentrations and the targeted delivery of CO to pathological tissues. To circumvent these problems, CO-releasing molecules (CORMs) have been developed and have been widely used as the alternative of gaseous CO to explore the physiological functions of CO and develop novel therapeutic agents. Unfortunately, conventional CORMs suffered from insufficient stability, short half-life, and poor biodistribution in biological conditions. Intriguingly, the encapsulation of CORMs into polymeric nanoparticles or covalently installation of CORMs to polymeric matrices remarkably improves the stability of CORMs, prolongs the releasing times and optimizes the biodistributions. In this review article, we summarize the recent achievements of CO-releasing macromolecules and three approaches used for the fabrication of CO-releasing macromolecules have been highlighted. Also, we envision the potential applications of these macromolecular CO donors and suggest future directions in this field. We hope that more efforts would be devoted to this emerging field to advance the clinical trial of macromolecular CO donors.
Carbon monoxide (CO) is a gaseous transmitter that has received mounting interest because of its therapeutic potentials in the treatment of inflammation, bacterial infection, cancer and so on. However, the clinical application of CO is remarkably hindered by the difficulty in precisely controlling CO concentrations and the targeted delivery of CO to pathological tissues. To circumvent these problems, CO-releasing molecules (CORMs) have been developed and have been widely used as the alternative of gaseous CO to explore the physiological functions of CO and develop novel therapeutic agents. Unfortunately, conventional CORMs suffered from insufficient stability, short half-life, and poor biodistribution in biological conditions. Intriguingly, the encapsulation of CORMs into polymeric nanoparticles or covalently installation of CORMs to polymeric matrices remarkably improves the stability of CORMs, prolongs the releasing times and optimizes the biodistributions. In this review article, we summarize the recent achievements of CO-releasing macromolecules and three approaches used for the fabrication of CO-releasing macromolecules have been highlighted. Also, we envision the potential applications of these macromolecular CO donors and suggest future directions in this field. We hope that more efforts would be devoted to this emerging field to advance the clinical trial of macromolecular CO donors.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191230001
Abstract:
An ortho-diamine monomer, 4-phenoxy-1,2-phenylenediamine (POPDA) was synthesized via two-step reactions. It was randomly copolymerized with 4,4’-dicarboxydiphenyl ether (DCDPE), 5-aminoisophthalic acid (APA) and 3,3’-diaminobenzidine (DAB) in polyphosphoric acid to yield a new kind of high molecular weight poly(ether ketone benzimidazole) copolymers (PEKBI-x, ‘x’ refers to the molar fraction of POPDA in aromatic diamines (POPDA and DAB), the same below). The resultant PEKBI-x was sulfonated using fuming sulfuric acid as the sulfonating reagent to give the corresponding sulfonated poly(ether ketone benzimidazole)s (SPEKBI-x). No significant polymer degradation was observed during the process of sulfonation reaction indicating excellent chemical stability of the copolymers PEKBI-x. A series of covalently cross-linked membranes (SPEKBI-x-CL) were prepared via solution cast method and the cross-linking reaction occurred between the amino groups of the APA moiety of the SPEKBI-x and the epoxy groups of the cross-linker 1,2,7,8-diepoxyoctane during the process of solvent evaporation. The thermal stability, mechanical properties, water uptake, swelling ratio, proton conductivity, ion exchange capacity, radical stability and single cell performance of the exchange proton membranes were investigated. Results showed that these cross-linked membranes exhibited very high ion exchange capacities (2.88～3.28 meq/g) and good mechanical and thermal properties. With the increase of POPDA content in the copolymers, the proton conductivity of the proton exchange membrane increased. A preliminary H2-O2 single cell test revealed that the maximum output power density of the single cell assembled with the SPEKBI-0.50-CL membrane reached 662 mW/ cm2 at 80 ℃, 80% relative humidity and 100 kPa back pressure, which was slightly higher than that of the one assemble with Nafion212 (631 mW/cm2) under the same test conditions.
An ortho-diamine monomer, 4-phenoxy-1,2-phenylenediamine (POPDA) was synthesized via two-step reactions. It was randomly copolymerized with 4,4’-dicarboxydiphenyl ether (DCDPE), 5-aminoisophthalic acid (APA) and 3,3’-diaminobenzidine (DAB) in polyphosphoric acid to yield a new kind of high molecular weight poly(ether ketone benzimidazole) copolymers (PEKBI-x, ‘x’ refers to the molar fraction of POPDA in aromatic diamines (POPDA and DAB), the same below). The resultant PEKBI-x was sulfonated using fuming sulfuric acid as the sulfonating reagent to give the corresponding sulfonated poly(ether ketone benzimidazole)s (SPEKBI-x). No significant polymer degradation was observed during the process of sulfonation reaction indicating excellent chemical stability of the copolymers PEKBI-x. A series of covalently cross-linked membranes (SPEKBI-x-CL) were prepared via solution cast method and the cross-linking reaction occurred between the amino groups of the APA moiety of the SPEKBI-x and the epoxy groups of the cross-linker 1,2,7,8-diepoxyoctane during the process of solvent evaporation. The thermal stability, mechanical properties, water uptake, swelling ratio, proton conductivity, ion exchange capacity, radical stability and single cell performance of the exchange proton membranes were investigated. Results showed that these cross-linked membranes exhibited very high ion exchange capacities (2.88～3.28 meq/g) and good mechanical and thermal properties. With the increase of POPDA content in the copolymers, the proton conductivity of the proton exchange membrane increased. A preliminary H2-O2 single cell test revealed that the maximum output power density of the single cell assembled with the SPEKBI-0.50-CL membrane reached 662 mW/ cm2 at 80 ℃, 80% relative humidity and 100 kPa back pressure, which was slightly higher than that of the one assemble with Nafion212 (631 mW/cm2) under the same test conditions.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191202002
Abstract:
An amphiphilic block copolymer（mPEG-S-S-PS） with a hydrophilic poly(ethylene glycol) methyl ether (mPEG) block, a hydrophobic polystyrene (PS) block and a disulfide linker was synthesized via atom transfer radical polymerization (ATRP). The structure and composition of mPEG-S-S-PS were characterized by nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Through solvent dispersion and microscopic observation, phase inversion of emulsions stabilized by mPEG-S-S-PS was studied. Thanks to the amphiphilic property of mPEG-S-S-PS and the insolubility of PS block in cyclohexane, the diblock copolymer self-assembled to form micelles composing of PS cores and mPEG coronas in water and to form inverse micelles composing of mPEG cores and PS coronas in cyclohexane. Therefore, for cyclohexane-water biphasic system with equal volumes, W/O type emulsions were preferred for copolymer initially dissolved in cyclohexane, while for copolymer initially dissolved in water, O/W type emulsions were obtained. However, for toluene-water biphasic systems, W/O type emulsions were always obtained no matter where the copolymers were dissolved because toluene was a non-selective and good solvent for both PS and mPEG blocks. Based on the redox responsiveness of mPEG-S-S-PS copolymer, the addition of reducing agent DTT or GSH could induce the phase inversion of toluene-water emulsion from W/O type to O/W type. The catastrophic phase inversion was obtained in this system by adjusting the oil-water volume ratio. When the proportion of water volume (φw) was smaller than 0.7, the emulsion was W/O type. However, with φw≥0.7, a catastrophic phase inversion occurred where the system shifted in the opposite direction and O/W type was obtained. These results will have potential applications in the field of controlled drug release.
An amphiphilic block copolymer（mPEG-S-S-PS） with a hydrophilic poly(ethylene glycol) methyl ether (mPEG) block, a hydrophobic polystyrene (PS) block and a disulfide linker was synthesized via atom transfer radical polymerization (ATRP). The structure and composition of mPEG-S-S-PS were characterized by nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Through solvent dispersion and microscopic observation, phase inversion of emulsions stabilized by mPEG-S-S-PS was studied. Thanks to the amphiphilic property of mPEG-S-S-PS and the insolubility of PS block in cyclohexane, the diblock copolymer self-assembled to form micelles composing of PS cores and mPEG coronas in water and to form inverse micelles composing of mPEG cores and PS coronas in cyclohexane. Therefore, for cyclohexane-water biphasic system with equal volumes, W/O type emulsions were preferred for copolymer initially dissolved in cyclohexane, while for copolymer initially dissolved in water, O/W type emulsions were obtained. However, for toluene-water biphasic systems, W/O type emulsions were always obtained no matter where the copolymers were dissolved because toluene was a non-selective and good solvent for both PS and mPEG blocks. Based on the redox responsiveness of mPEG-S-S-PS copolymer, the addition of reducing agent DTT or GSH could induce the phase inversion of toluene-water emulsion from W/O type to O/W type. The catastrophic phase inversion was obtained in this system by adjusting the oil-water volume ratio. When the proportion of water volume (φw) was smaller than 0.7, the emulsion was W/O type. However, with φw≥0.7, a catastrophic phase inversion occurred where the system shifted in the opposite direction and O/W type was obtained. These results will have potential applications in the field of controlled drug release.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20200111001
Abstract:
As one of the quasi-zero-dimensional materials, [60]fullerene (C60) and its organic/polymeric derivatives exhibit great application in many high-technology fields due to their outstanding optical, electronic, optoelectronic and magnetic properties. A new triphenylamine-fluorene copolymer-[60]fullerene covalently bridged triad (C60-PTF-C60) was synthesized by the 1,3-dipole addition reaction of C60, sarcosine and triphenylamine-fluorene PTF terminated with two aldehyde groups (CHO-PTF-CHO). C60-PTF-C60, which was highly soluble in some common organic solvents, was embedded into an optically nonactive transparent poly(methylmethlacrylate) (PMMA) matrix to produce the PMMA-based C60-PTF-C60 film for nonlinear optics. The nonlinear optical (NLO) and optical limiting (OL) properties of C60-PTF-C60 films were studied by Z-scan method. The open-aperture Z-scan results demonstrated that C60-PTF-C60/PMMA film exhibited more excellent nonlinear optical and optical limiting responses when compared to C60/PMMA film under the same experimental conditions due to photo-induced electron transfer between C60 and PTF in the copolymer structure. The achieved nonlinear coefficient (βeff), imaginary third-order susceptibility (Imχ(3)) and optical limiting threshold were 437.75 cm/GW1, 1.87×10−10 esu, and 0.34 GW/cm2, respectively. For comparison purpose, the corresponding βeff, Imχ(3) and limiting threshold of the C60/PMMA film were 188.87 cm/GW, 0.81×10−10 esu, and 0.53 GW/cm2, respectively.
As one of the quasi-zero-dimensional materials, [60]fullerene (C60) and its organic/polymeric derivatives exhibit great application in many high-technology fields due to their outstanding optical, electronic, optoelectronic and magnetic properties. A new triphenylamine-fluorene copolymer-[60]fullerene covalently bridged triad (C60-PTF-C60) was synthesized by the 1,3-dipole addition reaction of C60, sarcosine and triphenylamine-fluorene PTF terminated with two aldehyde groups (CHO-PTF-CHO). C60-PTF-C60, which was highly soluble in some common organic solvents, was embedded into an optically nonactive transparent poly(methylmethlacrylate) (PMMA) matrix to produce the PMMA-based C60-PTF-C60 film for nonlinear optics. The nonlinear optical (NLO) and optical limiting (OL) properties of C60-PTF-C60 films were studied by Z-scan method. The open-aperture Z-scan results demonstrated that C60-PTF-C60/PMMA film exhibited more excellent nonlinear optical and optical limiting responses when compared to C60/PMMA film under the same experimental conditions due to photo-induced electron transfer between C60 and PTF in the copolymer structure. The achieved nonlinear coefficient (βeff), imaginary third-order susceptibility (Imχ(3)) and optical limiting threshold were 437.75 cm/GW1, 1.87×10−10 esu, and 0.34 GW/cm2, respectively. For comparison purpose, the corresponding βeff, Imχ(3) and limiting threshold of the C60/PMMA film were 188.87 cm/GW, 0.81×10−10 esu, and 0.53 GW/cm2, respectively.
$v.latestStateEn
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190713001
Abstract:
The microstructure on the implants is essential for bone repairing and tissue regeneration. Especially, controllable preparation of well-defined micropattern is one of the key factors to regulate the biological fate of bone mesenchymal stem cells (BMSCs). Usually, the micropatterns are made of materials with limited degradability and poor bioactivity. In order to meet the needs for bone repairing and take the special structural and physiochemical properties of biomedical implants into account, the degradable hyaluronic acid (HA) was chosen as the raw material, cross-linked with N′-(ethyliminomethylidene)-N, N-dimethyl-1,3-propylene diamine (EDCI) and adipic acid dihydrazide (ADH). Soft-lithography technique was utilized to fabricate the HA microwell patterns. By turning the mass fractions of ADH and EDCI from 8.0% to 16.7% respectively, the effects of contents on the microstructure, swelling properties, degradation behavior, and compatibility of HA films were evaluated by a series of characterization methods.The experimental results showed that as the content of ADH and EDCI increased, the degree of crosslinking of the film was increased, and the swelling variation of gel became smaller. HA films with high content showed a slower degradation behavior. A series of HA films with micro-array pore structure (32, 96, 128 and 320 μm) respectively were successfully fabricated by combining soft lithography and solvent evaporation. When co-culture with rBMSCs in vitro, the results showed that the larger micron wells (96, 320 μm) with sparse distribution presented no significant effect on the proliferation of bone mesenchymal stem cells (rBMSCs) compared to the smooth HA gel film, while the small micron wells (d=32 μm) with compact distribution can significantly promote the proliferation and osteogenic activity of rBMSCs. Surprisingly, The pattern of 128 μm in diameter also promoted the proliferation of rBMSCs.
The microstructure on the implants is essential for bone repairing and tissue regeneration. Especially, controllable preparation of well-defined micropattern is one of the key factors to regulate the biological fate of bone mesenchymal stem cells (BMSCs). Usually, the micropatterns are made of materials with limited degradability and poor bioactivity. In order to meet the needs for bone repairing and take the special structural and physiochemical properties of biomedical implants into account, the degradable hyaluronic acid (HA) was chosen as the raw material, cross-linked with N′-(ethyliminomethylidene)-N, N-dimethyl-1,3-propylene diamine (EDCI) and adipic acid dihydrazide (ADH). Soft-lithography technique was utilized to fabricate the HA microwell patterns. By turning the mass fractions of ADH and EDCI from 8.0% to 16.7% respectively, the effects of contents on the microstructure, swelling properties, degradation behavior, and compatibility of HA films were evaluated by a series of characterization methods.The experimental results showed that as the content of ADH and EDCI increased, the degree of crosslinking of the film was increased, and the swelling variation of gel became smaller. HA films with high content showed a slower degradation behavior. A series of HA films with micro-array pore structure (32, 96, 128 and 320 μm) respectively were successfully fabricated by combining soft lithography and solvent evaporation. When co-culture with rBMSCs in vitro, the results showed that the larger micron wells (96, 320 μm) with sparse distribution presented no significant effect on the proliferation of bone mesenchymal stem cells (rBMSCs) compared to the smooth HA gel film, while the small micron wells (d=32 μm) with compact distribution can significantly promote the proliferation and osteogenic activity of rBMSCs. Surprisingly, The pattern of 128 μm in diameter also promoted the proliferation of rBMSCs.
$v.latestStateEn
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20200228002
Abstract:
A series of linear poly(dimethylsiloxane) (PDMS- g -Vi) with different vinyl contents were synthesized via ring-opening copolymerization of tetravinyltetramethylcyclotetrasiloxane (V4) and octamethylcyclotetrasiloxane (D4) catalyzed by a cyclic trimeric phosphazene base (CTPB). Further, the carboxylic acid- or amine-functionalized PDMSs (PDMS-g-COOH and PDMS-g-NH2) were prepared through the thiol-ene click reaction, confirmed by gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (1H-NMR). Finally, the target silicone elastomers (PDMS-g-[COOH/NH2]) were prepared based on the reversible ionic hydrogen bonds between COOH and NH2 side chain groups, exhibiting remarkably fast self-healing capability at room temperature without any external stimulus. The mechanical strength, elasticity and self-healing properties of resultant elastomers could be tuned by modulating the hydrogen bonding density and the molecular weight of PDMS-g-Vi precursors. The PDMS-g-[COOH/NH2] elastomer owned a breaking stress of 230.9 kPa at 877% elongation with a stretching speed at 50 mm/min and the elongation at break was higher than 500% even under a fast stretching speed (200 mm/min). Moreover, its self-healing efficiency reached as high as 99% after restored at room temperature for 30 min.
A series of linear poly(dimethylsiloxane) (PDMS- g -Vi) with different vinyl contents were synthesized via ring-opening copolymerization of tetravinyltetramethylcyclotetrasiloxane (V4) and octamethylcyclotetrasiloxane (D4) catalyzed by a cyclic trimeric phosphazene base (CTPB). Further, the carboxylic acid- or amine-functionalized PDMSs (PDMS-g-COOH and PDMS-g-NH2) were prepared through the thiol-ene click reaction, confirmed by gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (1H-NMR). Finally, the target silicone elastomers (PDMS-g-[COOH/NH2]) were prepared based on the reversible ionic hydrogen bonds between COOH and NH2 side chain groups, exhibiting remarkably fast self-healing capability at room temperature without any external stimulus. The mechanical strength, elasticity and self-healing properties of resultant elastomers could be tuned by modulating the hydrogen bonding density and the molecular weight of PDMS-g-Vi precursors. The PDMS-g-[COOH/NH2] elastomer owned a breaking stress of 230.9 kPa at 877% elongation with a stretching speed at 50 mm/min and the elongation at break was higher than 500% even under a fast stretching speed (200 mm/min). Moreover, its self-healing efficiency reached as high as 99% after restored at room temperature for 30 min.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191008001
Abstract:
Well-defined thermo-responsive tadpole-shaped double hydrophilic diblock copolymer (PEG45-b-cPNIPAM) was synthesized through the combination of atom transfer radical polymerization (ATRP) and intramolecular azide-alkynyl click chemistry reaction, where PEG was poly(ethylene glycol) and PNIPAM was poly(N-isopropylacrylamide). Firstly, PEG45(-alkynyl)-Br bearing an alkynyl end group and a bromo side group was synthesized as a macro-initiator to initiate the polymerization of N-isopropylacrylamide (NIPAM). Then, after the preparation of the thermo-responsive linear double hydrophilic diblock polymer, PEG45(-alkynyl)-b-PNIPAM-Cl, which had an alkynyl and a chloro group at the terminal of PEG and PNIPAM block, respectively. The chloro group was modified into azide group by the substitution reaction with sodium azide. Finally, via intramolecular azide-alkynyl click chemistry, PEG45-b-cPNIPAM was obtained, containing a cyclic PNIPAM “head” and a linear PEG “tail”. The structures of PEG45-b-cPNIPAM with different PNIPAM block lengths were characterized by Nuclear Magnetic Resonance (1H-NMR), Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FT-IR) and Laser Light Scattering (LLS) measurements. GPC results indicated that due to the smaller mean square radius of gyration, PEG45-b-cPNIPAM possessed lower molecular weight than its corresponding control linear diblock copolymer with the same length of PEG and PNIPAM block. Moreover, LLS results showed that the solution properties of the polymers were greatly affected by their topological structure. Upon being heated above the phase transition temperature, both the linear and tadpole-shaped diblock copolymer formed aggregates in aqueous solution due to the collapse of the PNIPAM blocks. However, the hydrodynamic radius, of the aggregates obtained from PEG-b-cPNIPAM was much smaller than that obtained from linear diblock copolymers with the same block length for lack of inter-chain entanglement. Besides, concerning the tadpole-shaped PEG45-b-cPNIPAM110 with longer PNIAPM block length, after the rapid phase transition, the collapsed polymer chains in the aggregates could further undergo conformation adjustment, thus resulting in the decrease in the size of aggregates with the increasing solution temperature.
Well-defined thermo-responsive tadpole-shaped double hydrophilic diblock copolymer (PEG45-b-cPNIPAM) was synthesized through the combination of atom transfer radical polymerization (ATRP) and intramolecular azide-alkynyl click chemistry reaction, where PEG was poly(ethylene glycol) and PNIPAM was poly(N-isopropylacrylamide). Firstly, PEG45(-alkynyl)-Br bearing an alkynyl end group and a bromo side group was synthesized as a macro-initiator to initiate the polymerization of N-isopropylacrylamide (NIPAM). Then, after the preparation of the thermo-responsive linear double hydrophilic diblock polymer, PEG45(-alkynyl)-b-PNIPAM-Cl, which had an alkynyl and a chloro group at the terminal of PEG and PNIPAM block, respectively. The chloro group was modified into azide group by the substitution reaction with sodium azide. Finally, via intramolecular azide-alkynyl click chemistry, PEG45-b-cPNIPAM was obtained, containing a cyclic PNIPAM “head” and a linear PEG “tail”. The structures of PEG45-b-cPNIPAM with different PNIPAM block lengths were characterized by Nuclear Magnetic Resonance (1H-NMR), Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FT-IR) and Laser Light Scattering (LLS) measurements. GPC results indicated that due to the smaller mean square radius of gyration, PEG45-b-cPNIPAM possessed lower molecular weight than its corresponding control linear diblock copolymer with the same length of PEG and PNIPAM block. Moreover, LLS results showed that the solution properties of the polymers were greatly affected by their topological structure. Upon being heated above the phase transition temperature, both the linear and tadpole-shaped diblock copolymer formed aggregates in aqueous solution due to the collapse of the PNIPAM blocks. However, the hydrodynamic radius, of the aggregates obtained from PEG-b-cPNIPAM was much smaller than that obtained from linear diblock copolymers with the same block length for lack of inter-chain entanglement. Besides, concerning the tadpole-shaped PEG45-b-cPNIPAM110 with longer PNIAPM block length, after the rapid phase transition, the collapsed polymer chains in the aggregates could further undergo conformation adjustment, thus resulting in the decrease in the size of aggregates with the increasing solution temperature.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191120001
Abstract:
Cellulose/sodium alginate (Cellu/SA) composite aerogels were prepared via freeze-drying technique as a valid method to develop 3D scaffolds for tissue engineering. Cellulose with hydroxyl groups showed weak apatite nucleation ability in simulated body fluid(SBF). In order to induce the formation of apatite crystal, oxidation modification of Cellu/SA composite aerogels was carried out with sodium periodate and sodium chlorite. The hydroxyl groups at C2 and C3 of Cellulose and SA were oxidized into carboxyl groups, leading to improve mineralization ability. The morphology and structure were characterized by Fourier Transform Infrared Spectrometer, Scan Electron Microscope, X-Ray Diffraction and X-ray Photoelectron Spectroscopy. Results show that the formation of HA on the surface of dicarboxylic Cellu/SA composite aerogels is faster with smaller grain size, and the deposition layer is more uniform after mineralization for 7 d. The Cellu/SA composite aerogels thus possess an ultrafine 3D nanoporous network structure. It is noticeable that the dicarboxylic Cellu/SA composite aerogel is a promising candidate for orthopedic biomaterial application with a Ca/P molar ratio of 1.35. In addition, the aerogel has good biocompatibility demonstrated by CCK8 assay and Live/Dead fluorescence staining of L929 cells. The L929 cells activity of both Cellu/SA and dicarboxylic Cellu/SA composite aerogels extracts are higher than 80%. When the culture duration is prolonged to 72 h, an obvious increase in the intensity of green fluorescence is observed, suggesting that the number of cells is increased. The biocompatible mineralized dicarboxylic Cellu/SA composite aerogels can promote cell growth and differentiation and are potential to be applied as a bone repair material.
Cellulose/sodium alginate (Cellu/SA) composite aerogels were prepared via freeze-drying technique as a valid method to develop 3D scaffolds for tissue engineering. Cellulose with hydroxyl groups showed weak apatite nucleation ability in simulated body fluid(SBF). In order to induce the formation of apatite crystal, oxidation modification of Cellu/SA composite aerogels was carried out with sodium periodate and sodium chlorite. The hydroxyl groups at C2 and C3 of Cellulose and SA were oxidized into carboxyl groups, leading to improve mineralization ability. The morphology and structure were characterized by Fourier Transform Infrared Spectrometer, Scan Electron Microscope, X-Ray Diffraction and X-ray Photoelectron Spectroscopy. Results show that the formation of HA on the surface of dicarboxylic Cellu/SA composite aerogels is faster with smaller grain size, and the deposition layer is more uniform after mineralization for 7 d. The Cellu/SA composite aerogels thus possess an ultrafine 3D nanoporous network structure. It is noticeable that the dicarboxylic Cellu/SA composite aerogel is a promising candidate for orthopedic biomaterial application with a Ca/P molar ratio of 1.35. In addition, the aerogel has good biocompatibility demonstrated by CCK8 assay and Live/Dead fluorescence staining of L929 cells. The L929 cells activity of both Cellu/SA and dicarboxylic Cellu/SA composite aerogels extracts are higher than 80%. When the culture duration is prolonged to 72 h, an obvious increase in the intensity of green fluorescence is observed, suggesting that the number of cells is increased. The biocompatible mineralized dicarboxylic Cellu/SA composite aerogels can promote cell growth and differentiation and are potential to be applied as a bone repair material.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190810001
Abstract:
A series of microporous organic polymers (MOPs) were synthesized by a one-step oxidative coupling reaction using carbazole-functionalized siloles, such as 1,1-dimethyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole, 1-methyl-1-phenyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole and 1,1-diphenyl-3,4-diphenyl-2,5-bis(4'- (9H-car bazol-9-yl)-phenyl)silole. The structure and properties of the three MOPs were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric (TG) analysis, field emission scanning electron microscope（FSEM） and transmission electron microscope (TEM). FT-IR spectra indicated the success of the oxidative coupling reaction for constructing the polymer frameworks. XRD measurements revealed that all the polymer frameworks were amorphous solid in nature. These MOPs exhibited high thermal stability with the onset of decomposition temperature above 400 ℃ at 5% mass loss under nitrogen flow. The nitrogen adsorption test showed that the specific surface area of the polymers ranged from 587 m2/g to 617 m2/g. There was a rigid main chain and nitrogen-rich conjugate structure of microporous skeleton material. The CO2 adsorption of CPDM-CzS was 2.1 mmol/g (113 kPa, 273 K) and the H2 adsorption of CPPM-CzS was 1.51% (113 kPa, 77 K）. In addition, CPDM-CzS showed excellent selectivity of adsorption performance of 75.2 for CO2/N2. These microporous frameworks will have prospective applications in gas adsorption and separation.
A series of microporous organic polymers (MOPs) were synthesized by a one-step oxidative coupling reaction using carbazole-functionalized siloles, such as 1,1-dimethyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole, 1-methyl-1-phenyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole and 1,1-diphenyl-3,4-diphenyl-2,5-bis(4'- (9H-car bazol-9-yl)-phenyl)silole. The structure and properties of the three MOPs were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric (TG) analysis, field emission scanning electron microscope（FSEM） and transmission electron microscope (TEM). FT-IR spectra indicated the success of the oxidative coupling reaction for constructing the polymer frameworks. XRD measurements revealed that all the polymer frameworks were amorphous solid in nature. These MOPs exhibited high thermal stability with the onset of decomposition temperature above 400 ℃ at 5% mass loss under nitrogen flow. The nitrogen adsorption test showed that the specific surface area of the polymers ranged from 587 m2/g to 617 m2/g. There was a rigid main chain and nitrogen-rich conjugate structure of microporous skeleton material. The CO2 adsorption of CPDM-CzS was 2.1 mmol/g (113 kPa, 273 K) and the H2 adsorption of CPPM-CzS was 1.51% (113 kPa, 77 K）. In addition, CPDM-CzS showed excellent selectivity of adsorption performance of 75.2 for CO2/N2. These microporous frameworks will have prospective applications in gas adsorption and separation.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190520001
Abstract:
Quaternized chitosan/nano-zinc oxide (QAC/ZnO) hybrid colloidal particles were prepared by the self-assembly of quaternized chitosan (QAC), L-cysteine (L-cys) and the precursor of nano-zinc oxide Zn(CH3COO)2·2H2O. The chemical composition of QAC/ZnO hybrid colloidal particles was determined by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetic analysis(TG). The morphology and particle size of the hybrid colloidal particles were investigated in detail by means of Zeta potential analyzer, nanoparticle size analyzer and transmission electron microscopy (TEM). The ultraviolet transmittance, oxidation resistance, photocatalytic activity and cytotoxicity of the hybrid colloidal particles were studied by UV-Vis spectroscopy and the in vitro cell experiments. The results show that spherical QAC/ZnO hybrid colloidal particles can be successfully prepared by the self-assembly of QAC,
Quaternized chitosan/nano-zinc oxide (QAC/ZnO) hybrid colloidal particles were prepared by the self-assembly of quaternized chitosan (QAC), L-cysteine (L-cys) and the precursor of nano-zinc oxide Zn(CH3COO)2·2H2O. The chemical composition of QAC/ZnO hybrid colloidal particles was determined by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetic analysis(TG). The morphology and particle size of the hybrid colloidal particles were investigated in detail by means of Zeta potential analyzer, nanoparticle size analyzer and transmission electron microscopy (TEM). The ultraviolet transmittance, oxidation resistance, photocatalytic activity and cytotoxicity of the hybrid colloidal particles were studied by UV-Vis spectroscopy and the in vitro cell experiments. The results show that spherical QAC/ZnO hybrid colloidal particles can be successfully prepared by the self-assembly of QAC,
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190819001
Abstract:
A highly efficient and simple method for preparing small-size Janus gold nanoparticles (AuNPs) capable of self-assembling was developed. Firstly, the asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were fabricated based on β-cyclodextrin (β-CD) by combining atom transfer radical polymerization (ATRP) and click chemistry. Secondary, the hydroxyl groups on the wide cross-section of the β-CD molecule were modified to be ATRP initiator moieties, which then initiated the polymerization of N-isopropyl acrylamide (NIPAM) to form fourteen PNIPAM chains via ATRP. The primary hydroxyl groups on the narrow cross-section of the β-CD molecule were converted into azide groups and then coupled with 5-(1,2-dithiolan-3-yl)-N-(prop-2-ynyl) pentanamide molecules by click chemistry. The obtained asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were used to modify AuNPs that were formerly surface-stabilized by n-butylthiol through the ligand exchange process. Due to the steric effect of (LA)7-CD-(PNIPAM46)14 macromolecules, Janus hybrid AuNPs, Au3.1-CD-(PNIPAM46)14, with amphiphilic surface were prepared, which could self-assemble in water into micelle-like aggregates, i.e. supermicelles. The chemical and chain structures of asymmetric (LA)7-CD-(PNIPAM46)14 star polymers and the amphiphilic Janus hybrid Au3.1-CD-(PNIPAM46)14 nanoparticles were characterized by Nuclear Magnetic Resonance (NMR), Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS), Gel Permeation Chromatography (GPC) and Thermal Gravimetric (TG) analysis. The morphology and structure of the prepared micelle-like self-assemblies were investigated by Transmission Electron Microscope (TEM).
A highly efficient and simple method for preparing small-size Janus gold nanoparticles (AuNPs) capable of self-assembling was developed. Firstly, the asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were fabricated based on β-cyclodextrin (β-CD) by combining atom transfer radical polymerization (ATRP) and click chemistry. Secondary, the hydroxyl groups on the wide cross-section of the β-CD molecule were modified to be ATRP initiator moieties, which then initiated the polymerization of N-isopropyl acrylamide (NIPAM) to form fourteen PNIPAM chains via ATRP. The primary hydroxyl groups on the narrow cross-section of the β-CD molecule were converted into azide groups and then coupled with 5-(1,2-dithiolan-3-yl)-N-(prop-2-ynyl) pentanamide molecules by click chemistry. The obtained asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were used to modify AuNPs that were formerly surface-stabilized by n-butylthiol through the ligand exchange process. Due to the steric effect of (LA)7-CD-(PNIPAM46)14 macromolecules, Janus hybrid AuNPs, Au3.1-CD-(PNIPAM46)14, with amphiphilic surface were prepared, which could self-assemble in water into micelle-like aggregates, i.e. supermicelles. The chemical and chain structures of asymmetric (LA)7-CD-(PNIPAM46)14 star polymers and the amphiphilic Janus hybrid Au3.1-CD-(PNIPAM46)14 nanoparticles were characterized by Nuclear Magnetic Resonance (NMR), Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS), Gel Permeation Chromatography (GPC) and Thermal Gravimetric (TG) analysis. The morphology and structure of the prepared micelle-like self-assemblies were investigated by Transmission Electron Microscope (TEM).
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190619002
Abstract:
Firstly, a series of bio-based poly(isosorbide dicarboxylate) diols (PISA) were synthesized by the reactions between bio-based isosorbide (IS) and five kinds of dicarboxylic acids with different methylene chain lengths. Then, bio-based polyurethane (Bio-PU) was prepared by the reaction between 4,4'-diphenylmethane diisocyanate (MDI) with PISA and 1,4-butanediol (BDO) as the chain extender. The structure and thermal properties of PISA samples were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H-NMR) and differential scanning calorimeter (DSC). The structure and properties of Bio-PU were characterized by FT-IR, DSC, dynamic mechanical thermal analyzer (DMA), atomic force microscope (AFM), water contact angle test and measurement of mechanical properties. Results showed that Mn of PISA were in the range between 672 and 940. As the carbon numbers in repeating units of PISA increased from 4 to 12, the glass transition temperature (Tg) of PISA samples decreased from 10.5 °C to −40.9 ℃. The viscosity also decreased, but the crystallinity increased. When the length of methylene chain in the repeating unit of PISA increased, the hydrogen bonding of Bio-PU decreased. Tg values decreased from 114 °C to 71.4 °C. The yield strength, Young's modulus and Shore D hardness decreased from 62.9, 2 042 MPa and 80 to 53.4, 1 070 MPa and 72, respectively. The hydrophilicity also decreased. However, the tensile strength and elongation at break were improved appreciably from 36.0 MPa and 46% to 64.5 MPa and 220%, respectively. A new way to prepare Bio-PU with high rigidity and mechanical properties from IS is provided.
Firstly, a series of bio-based poly(isosorbide dicarboxylate) diols (PISA) were synthesized by the reactions between bio-based isosorbide (IS) and five kinds of dicarboxylic acids with different methylene chain lengths. Then, bio-based polyurethane (Bio-PU) was prepared by the reaction between 4,4'-diphenylmethane diisocyanate (MDI) with PISA and 1,4-butanediol (BDO) as the chain extender. The structure and thermal properties of PISA samples were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H-NMR) and differential scanning calorimeter (DSC). The structure and properties of Bio-PU were characterized by FT-IR, DSC, dynamic mechanical thermal analyzer (DMA), atomic force microscope (AFM), water contact angle test and measurement of mechanical properties. Results showed that Mn of PISA were in the range between 672 and 940. As the carbon numbers in repeating units of PISA increased from 4 to 12, the glass transition temperature (Tg) of PISA samples decreased from 10.5 °C to −40.9 ℃. The viscosity also decreased, but the crystallinity increased. When the length of methylene chain in the repeating unit of PISA increased, the hydrogen bonding of Bio-PU decreased. Tg values decreased from 114 °C to 71.4 °C. The yield strength, Young's modulus and Shore D hardness decreased from 62.9, 2 042 MPa and 80 to 53.4, 1 070 MPa and 72, respectively. The hydrophilicity also decreased. However, the tensile strength and elongation at break were improved appreciably from 36.0 MPa and 46% to 64.5 MPa and 220%, respectively. A new way to prepare Bio-PU with high rigidity and mechanical properties from IS is provided.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191115002
Abstract:
A novel type of microcapsule with pH-responsive release and anti-corrosion function was prepared via the UV-initiated polymerization and interfacial polymerization of Pickering emulsion. Then the microcapsule was loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) and embedded into epoxy coating for enhancing the anti-corrosion performance of coating. SiO2 nanoparticles were used as the Pickering emulsifier to stabilize the oil phase of emulsion, which contained aniline, glycidyl methacrylate (GMA) and 1,6-hexanediol diacrylate (HDDA). GMA and HDDA underwent crosslinking along with the interior of the emulsion droplets and formed the first shell of microcapsule initiated by UV light. The polyaniline (PANI) was synthesized subsequently via chemical oxidative polymerization of aniline initiated by ammonium persulfate (APS) and acted as the second functional layer of microcapsule shell material. The shell of the as-prepared PGMA@PANI microcapsule is thus of composite structure. The PGMA shell stabilized the morphology of the emulsion droplets and improved the robustness of the microcapsule. The PANI shell functioned as anti-corrosion filler and a pH-sensitive gatekeeper to realize the responsive release of corrosion inhibitor. After loaded MBT, the MBT-PGMA@PANI microcapsule could achieve dual anti-corrosion function. PANI could passivate the steel and released MBT could form dense barrier layer on the steel surface to resist corrosive medium. Electrochemical impedance spectroscopy (EIS) was used to test the performance of coating. The Bode plots showed that the impedance values at low frequency (|Z|f=0.1 Hz) of coating with 1% mass fracion of MBT-PGMA@PANI microcapsule could be maintain above 108 Ω·cm2 after immersed in NaCl solution (w=3.5%) for 30 d, demonstrating significant improvement of anti-corrosion performance.
A novel type of microcapsule with pH-responsive release and anti-corrosion function was prepared via the UV-initiated polymerization and interfacial polymerization of Pickering emulsion. Then the microcapsule was loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) and embedded into epoxy coating for enhancing the anti-corrosion performance of coating. SiO2 nanoparticles were used as the Pickering emulsifier to stabilize the oil phase of emulsion, which contained aniline, glycidyl methacrylate (GMA) and 1,6-hexanediol diacrylate (HDDA). GMA and HDDA underwent crosslinking along with the interior of the emulsion droplets and formed the first shell of microcapsule initiated by UV light. The polyaniline (PANI) was synthesized subsequently via chemical oxidative polymerization of aniline initiated by ammonium persulfate (APS) and acted as the second functional layer of microcapsule shell material. The shell of the as-prepared PGMA@PANI microcapsule is thus of composite structure. The PGMA shell stabilized the morphology of the emulsion droplets and improved the robustness of the microcapsule. The PANI shell functioned as anti-corrosion filler and a pH-sensitive gatekeeper to realize the responsive release of corrosion inhibitor. After loaded MBT, the MBT-PGMA@PANI microcapsule could achieve dual anti-corrosion function. PANI could passivate the steel and released MBT could form dense barrier layer on the steel surface to resist corrosive medium. Electrochemical impedance spectroscopy (EIS) was used to test the performance of coating. The Bode plots showed that the impedance values at low frequency (|Z|f=0.1 Hz) of coating with 1% mass fracion of MBT-PGMA@PANI microcapsule could be maintain above 108 Ω·cm2 after immersed in NaCl solution (w=3.5%) for 30 d, demonstrating significant improvement of anti-corrosion performance.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190424004
Abstract:
Semiconductor photocatalysts can directly use sunlight to produce clean and renewable energy, offering a potentially viable solution for addressing energy and environmental crisis. Recently, conjugated microporous polymers have emerged as a very promising class of materials in solar energy conversion. However, they generally exhibit low catalytic efficiency and insufficient catalytic stability. Moreover, they lack the capability to utilize long-wavelength photons in the near-infrared region. In this work, aza-fused conjugated microporous polymer (aza-CMP) is synthesize via condensation of 1,2,4,5-benzenetetramine and cyclohexanone. The as-obtained aza-CMP exhibits a band-gap as low as 1.22 eV, ensuring that it can absorb both visible light and nea-infrared photons. Meanwhile, results show that aza-CMP can effectively drive the degradation of various organic dyes such as Congo Red, Rhodamine B, and Methyl Orange under visible and near-infrared light irradiation. In contrast, other photocatalysts such as P25-TiO2, g-C3N4, and Ag-TiO2 are unable to oxidize organic dyes under near-infrared light irradiation, suggesting that aza-CMP is very efficient in absorbing visible and long-wavelength photons for photocatalytic oxidation of organic pollutants. In addition, multiple cycling experiments confirm that aza-CMP is very stable during the catalytic process, which can retain its structure and high catalytic activity after multiple cycles. Mechanistic investigations further reveal that the active species toward photocatalytic degradation of organic dyes are the photogenerated holes and singlet oxygen. Furthermore, the pathways of the photocatalytic degradation of organic dyes are unveiled by using liquid chromatography-mass spectrometry (LC-MS), clearly demonstrating the capability of aza-CMP in oxidizing organic dyes into small molecules. This study potentially provides new prospects in the design and synthesis of conjugated polymers for various photocatalytic applications.
Semiconductor photocatalysts can directly use sunlight to produce clean and renewable energy, offering a potentially viable solution for addressing energy and environmental crisis. Recently, conjugated microporous polymers have emerged as a very promising class of materials in solar energy conversion. However, they generally exhibit low catalytic efficiency and insufficient catalytic stability. Moreover, they lack the capability to utilize long-wavelength photons in the near-infrared region. In this work, aza-fused conjugated microporous polymer (aza-CMP) is synthesize via condensation of 1,2,4,5-benzenetetramine and cyclohexanone. The as-obtained aza-CMP exhibits a band-gap as low as 1.22 eV, ensuring that it can absorb both visible light and nea-infrared photons. Meanwhile, results show that aza-CMP can effectively drive the degradation of various organic dyes such as Congo Red, Rhodamine B, and Methyl Orange under visible and near-infrared light irradiation. In contrast, other photocatalysts such as P25-TiO2, g-C3N4, and Ag-TiO2 are unable to oxidize organic dyes under near-infrared light irradiation, suggesting that aza-CMP is very efficient in absorbing visible and long-wavelength photons for photocatalytic oxidation of organic pollutants. In addition, multiple cycling experiments confirm that aza-CMP is very stable during the catalytic process, which can retain its structure and high catalytic activity after multiple cycles. Mechanistic investigations further reveal that the active species toward photocatalytic degradation of organic dyes are the photogenerated holes and singlet oxygen. Furthermore, the pathways of the photocatalytic degradation of organic dyes are unveiled by using liquid chromatography-mass spectrometry (LC-MS), clearly demonstrating the capability of aza-CMP in oxidizing organic dyes into small molecules. This study potentially provides new prospects in the design and synthesis of conjugated polymers for various photocatalytic applications.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190705001
Abstract:
Polyimides (PIs) have extensive applications in the aerospace industry, microelectronic and optoelectronic engineering, liquid crystal display, and separation membrane due to their high-temperature resistance, outstanding mechanical properties, chemical and radiation resistance, and excellent dielectric properties. Conventional PIs possess strong inter- and intra- molecular charge transfer interactions, resulting in an intense stack of the molecular chains, which leads to strong absorption in the visible region and brings deep color to PIs. This has considerably restricted their applications in the area of optoelectronic and microelectronic engineering. With the rapid development of display technology, PIs with excellent optical and thermal performance are desired to serve as substrate materials. However, achieving a breakthrough in the molecular design of the satisfied PIs remains challenging with regarding to the trade-off between good transparency and thermal stability of PI films. Recently, enormous research efforts have been devoted to the development of colorless and transparent PIs with high thermal stability via rational molecular structure design, as summarized in this review. These fabrication strategies mainly include the introduction of strong electronegative groups, alicyclic structures, bulky pendent units, asymmetric and rigid noncoplanar segments, and polymerizable inorganic nanoparticles. The incorporation of these structures plays an important role in disrupting the conjugation between the PI chains. This disruption reduces the regularity and weakens the stack of the molecular chains, while increasing the free volume of the PI chains, thus prohibiting the formation of inter- and intra- molecular charge transfer complex. All these are beneficial to minimize the absorption in the visible region and the formation of colorless PIs. Then, the influences of molecular structures on the properties of PI, such as thermal properties, optical performance, and solubility, are discussed. Finally, the prospect of colorless and transparent PI with high thermal stability is discussed with respect to their development trends and potential applications.
Polyimides (PIs) have extensive applications in the aerospace industry, microelectronic and optoelectronic engineering, liquid crystal display, and separation membrane due to their high-temperature resistance, outstanding mechanical properties, chemical and radiation resistance, and excellent dielectric properties. Conventional PIs possess strong inter- and intra- molecular charge transfer interactions, resulting in an intense stack of the molecular chains, which leads to strong absorption in the visible region and brings deep color to PIs. This has considerably restricted their applications in the area of optoelectronic and microelectronic engineering. With the rapid development of display technology, PIs with excellent optical and thermal performance are desired to serve as substrate materials. However, achieving a breakthrough in the molecular design of the satisfied PIs remains challenging with regarding to the trade-off between good transparency and thermal stability of PI films. Recently, enormous research efforts have been devoted to the development of colorless and transparent PIs with high thermal stability via rational molecular structure design, as summarized in this review. These fabrication strategies mainly include the introduction of strong electronegative groups, alicyclic structures, bulky pendent units, asymmetric and rigid noncoplanar segments, and polymerizable inorganic nanoparticles. The incorporation of these structures plays an important role in disrupting the conjugation between the PI chains. This disruption reduces the regularity and weakens the stack of the molecular chains, while increasing the free volume of the PI chains, thus prohibiting the formation of inter- and intra- molecular charge transfer complex. All these are beneficial to minimize the absorption in the visible region and the formation of colorless PIs. Then, the influences of molecular structures on the properties of PI, such as thermal properties, optical performance, and solubility, are discussed. Finally, the prospect of colorless and transparent PI with high thermal stability is discussed with respect to their development trends and potential applications.
Effect of Metal Ion Loading on Thermal Decomposition Temperature of Surface Modified Polyimide Films
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191119001
Abstract:
The surface of the pyromellitic anhydride/4,4'-diaminodiphenyl ether (PMDA/ODA)-based polyimide (PI) film was subjected to alkali-cleaving and ring-opening treatment with potassium hydroxide (KOH) solution. After acidification with acetic acid, a surface-modificated layer of polyamic acid (PAA) was obtained on the surface of PI. Six different metal ions of K+, Na+, Ca2+, Mg2+, Ag+ and Al3+ were introduced into the PAA layer via ion exchange reaction. The ion exchange processes of different metal ions were investigated with Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and inductively coupled plasma emission spectroscopy (ICP). As a result, the load amount of metal ion showed a completely inverse relationship with its valence, indicating that the ion exchange reaction was carried out exactly according to the ionic charge ratio of 1∶1. Meanwhile, the thermal gravimetric analyzer (TG) under nitrogen atmosphere was performed to investigate the effect of different metal ions on the thermal decomposition temperature of polyimide films. It was found that the strong alkali metal ions K+ and Na+ provided obvious degradation effects on the PI films, which caused a significant decrease in the thermal decomposition temperature of the PI films. However, the weaker alkali metal ions such as Ca2+, Mg2+, Ag+ and Al3+ exhibited a rather weak influence on the thermal decomposition temperature of the PI films. The effect of reducing the thermal decomposition temperature was positively correlated with metal basicity（pKb）, ie K+> Na+ >> Ca2+ ≈ Mg2+ > Ag+ ≈ Al3+.
The surface of the pyromellitic anhydride/4,4'-diaminodiphenyl ether (PMDA/ODA)-based polyimide (PI) film was subjected to alkali-cleaving and ring-opening treatment with potassium hydroxide (KOH) solution. After acidification with acetic acid, a surface-modificated layer of polyamic acid (PAA) was obtained on the surface of PI. Six different metal ions of K+, Na+, Ca2+, Mg2+, Ag+ and Al3+ were introduced into the PAA layer via ion exchange reaction. The ion exchange processes of different metal ions were investigated with Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and inductively coupled plasma emission spectroscopy (ICP). As a result, the load amount of metal ion showed a completely inverse relationship with its valence, indicating that the ion exchange reaction was carried out exactly according to the ionic charge ratio of 1∶1. Meanwhile, the thermal gravimetric analyzer (TG) under nitrogen atmosphere was performed to investigate the effect of different metal ions on the thermal decomposition temperature of polyimide films. It was found that the strong alkali metal ions K+ and Na+ provided obvious degradation effects on the PI films, which caused a significant decrease in the thermal decomposition temperature of the PI films. However, the weaker alkali metal ions such as Ca2+, Mg2+, Ag+ and Al3+ exhibited a rather weak influence on the thermal decomposition temperature of the PI films. The effect of reducing the thermal decomposition temperature was positively correlated with metal basicity（pKb）, ie K+> Na+ >> Ca2+ ≈ Mg2+ > Ag+ ≈ Al3+.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191015001
Abstract:
With the increasing pollution of marine plastics, the degradation properties of biodegradable plastics in seawater have attracted much attention and controversy. Four typical biodegradable plastics polylactide (PLA), poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS) and poly(ε-caprolactone) (PCL) were selected. The seawater degradability of the materials was studied by investigation of the change in their mass loss, molecular weight, mechanical properties, and spline morphology after 364 d immersed in natural seawater. Further, the effects of environmental factors on the degradation properties of four polyesters were studied in natural water, static seawater, static river water, distilled water, sterilized seawater, and lab-prepared seawater. Results show that the degradability of biodegradable polyester in natural seawater is significantly lower than that in compost. The most market- demand PLA almost exhibits no degradation after 364 d. The mass losses of PBAT and PBS are no more than 3% after 364 d. PCL degrades fastest and gets the mass loss of 32%. Microorganisms seem to be the key factors affecting the rate of biodegradation. It is also foud that the high concentration of inorganic salts has a promotion to the non-enzymatic hydrolysis process.
With the increasing pollution of marine plastics, the degradation properties of biodegradable plastics in seawater have attracted much attention and controversy. Four typical biodegradable plastics polylactide (PLA), poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS) and poly(ε-caprolactone) (PCL) were selected. The seawater degradability of the materials was studied by investigation of the change in their mass loss, molecular weight, mechanical properties, and spline morphology after 364 d immersed in natural seawater. Further, the effects of environmental factors on the degradation properties of four polyesters were studied in natural water, static seawater, static river water, distilled water, sterilized seawater, and lab-prepared seawater. Results show that the degradability of biodegradable polyester in natural seawater is significantly lower than that in compost. The most market- demand PLA almost exhibits no degradation after 364 d. The mass losses of PBAT and PBS are no more than 3% after 364 d. PCL degrades fastest and gets the mass loss of 32%. Microorganisms seem to be the key factors affecting the rate of biodegradation. It is also foud that the high concentration of inorganic salts has a promotion to the non-enzymatic hydrolysis process.
Preparation of Polyurethane/Nano-TiO2 Hybrid Materials Containing Alkyl Side Chains in Soft Segments
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190809001
Abstract:
Two well-defined comb-like polyester diols (GS) with C-18 side chains were synthesized by reacting glyceryl monostearate (GMS) with succinic anhydride. NCO-terminated polyurethane prepolymers (PUGS) with C-18 side chains in soft segment structure were synthesized from diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO) and GS. Then polyurethane hybrid materials (PUGS-Ti) were further prepared by mixing with nano-TiO2. The structures of GS and PUGS were characterized by 1H-NMR and FT-IR. The crystallization behavior, surface morphology and surface contact angle of the prepared PUGS and its hybrid material were characterized by DSC, WAXD, SEM, AFM and water contact angle measurements. The effects of alkyl side chain content and the amount of TiO2 on the surface properties of PUGS and its hybrid material were investigated. Results showed that the introduction of non-polar alkyl side chains into the polyurethane could significantly reduce the surface energy and increase the contact angles of water on the surface, approaching to the contact angle of water on the surface of the fluorine-containing polyurethane. In PUGS-Ti, the surface energy of the materials could be effectively adjusted to achieve superhydrophobicity of the surface by adjusting the content of soft segments (the number of alkyl side chains) and the amount of TiO2 in the structure.
Two well-defined comb-like polyester diols (GS) with C-18 side chains were synthesized by reacting glyceryl monostearate (GMS) with succinic anhydride. NCO-terminated polyurethane prepolymers (PUGS) with C-18 side chains in soft segment structure were synthesized from diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO) and GS. Then polyurethane hybrid materials (PUGS-Ti) were further prepared by mixing with nano-TiO2. The structures of GS and PUGS were characterized by 1H-NMR and FT-IR. The crystallization behavior, surface morphology and surface contact angle of the prepared PUGS and its hybrid material were characterized by DSC, WAXD, SEM, AFM and water contact angle measurements. The effects of alkyl side chain content and the amount of TiO2 on the surface properties of PUGS and its hybrid material were investigated. Results showed that the introduction of non-polar alkyl side chains into the polyurethane could significantly reduce the surface energy and increase the contact angles of water on the surface, approaching to the contact angle of water on the surface of the fluorine-containing polyurethane. In PUGS-Ti, the surface energy of the materials could be effectively adjusted to achieve superhydrophobicity of the surface by adjusting the content of soft segments (the number of alkyl side chains) and the amount of TiO2 in the structure.
, Available online ,
doi: 10.14133/j.cnki.1008-9357.20190617001
Abstract:
Periodic micro-grooves with different widths (20, 40 μm and 60 μm) on the surface of polyetheretherketone (PEEK)/mesoporous calcium magnesium silicate (m-CMS) composite were prepared by femtosecond laser. The effects of the width of micro-grooves on the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) were investigated. Results showed that the micro-nanostructures were formed in the inner surface of the micro-grooves after ablating using femtosecond laser, which exhibited a large number of mesoporous calcium magnesium silicate particles. In addition, the roughness (Ra = 5.15 μm) of the inner surface of the micro-grooves was significantly improved as compared with the grooved ridge (Ra = 1.53 μm) that was absent of treatment by femtosecond laser. Moreover, with the increase of the width of the micro-grooves, the protein adsorption of the composite surface was obviously enhanced, which significantly promoted the adhesion of rBMSCs on the composite surface. Furthermore, when the width of the micro-grooves was 20 μm, the cells did not display specific growth orientation on the composite surface. When the width of the micro-groove was 40 μm, a small number of cells grew along the groove orientation. When the width of the groove was 60 μm, a large number of cells grew along the groove orientation, and the cell body was plump with filamentous pseudopodia extending, which indicated that the composite surface not only significantly promoted the adhesion, spreading, proliferation and osteogenic differentiation of cells, but also induced the growth of cells along the groove orientation. In short, periodic micro-grooves on the composite surface were prepared by femtosecond laser, and the width of micro-grooves on the composite surface could regulate and control the behaviors of cells, in which appropriate width (e.g. 60 μm) of micro-grooves was conducive to stimulate cell responses.
Periodic micro-grooves with different widths (20, 40 μm and 60 μm) on the surface of polyetheretherketone (PEEK)/mesoporous calcium magnesium silicate (m-CMS) composite were prepared by femtosecond laser. The effects of the width of micro-grooves on the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) were investigated. Results showed that the micro-nanostructures were formed in the inner surface of the micro-grooves after ablating using femtosecond laser, which exhibited a large number of mesoporous calcium magnesium silicate particles. In addition, the roughness (Ra = 5.15 μm) of the inner surface of the micro-grooves was significantly improved as compared with the grooved ridge (Ra = 1.53 μm) that was absent of treatment by femtosecond laser. Moreover, with the increase of the width of the micro-grooves, the protein adsorption of the composite surface was obviously enhanced, which significantly promoted the adhesion of rBMSCs on the composite surface. Furthermore, when the width of the micro-grooves was 20 μm, the cells did not display specific growth orientation on the composite surface. When the width of the micro-groove was 40 μm, a small number of cells grew along the groove orientation. When the width of the groove was 60 μm, a large number of cells grew along the groove orientation, and the cell body was plump with filamentous pseudopodia extending, which indicated that the composite surface not only significantly promoted the adhesion, spreading, proliferation and osteogenic differentiation of cells, but also induced the growth of cells along the groove orientation. In short, periodic micro-grooves on the composite surface were prepared by femtosecond laser, and the width of micro-grooves on the composite surface could regulate and control the behaviors of cells, in which appropriate width (e.g. 60 μm) of micro-grooves was conducive to stimulate cell responses.
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, Available online ,
doi: 10.14133/j.cnki.1008-9357.20191208001
Abstract:
Graphene oxide (GO) nanosheets with varied mass contents (0%, 0.5%, 1% and 2%) were introduced into the shape memory capable poly(lactide-co-caprolactone) (PLCL) copolymer to prepare GO/PLCL composite nanofibers via electrospinning. Based on the tensile and shape memory properties of the produced GO/PLCL nanofibrous mats, an optimal content of GO (0.5%) was determined to maximize the reinforcing effect of the GO nanosheets to the PLCL fiber matrix. Thereafter, an alkaline amino acid lysine (Lys) was selected to functionalize the GO (0.5%) via EDC/NHS chemistry followed by electrospinning for the generation of multifunctional Lys-GO/PLCL nanofibers. A series of characterization including fiber morphology, mechanical properties, shape memory performance, acidity neutralization capacity and osteogenic differentiation by using the mouse bone mesenchymal stem cells (rBMSCs) were subsequently carried out with the produced Lys-GO/PLCL nanofibers. The results showed that among the four groups of GO/PLCL nanofibers loaded with different GO mass fractions (i.e., 0%, 0.5%, 1% and 2%), incorporation of 0.5% GO within the PLCL nanofibers gave rise to the most remarkable enhancement efficiency, as evidenced by the noted 28.4% increase in Young's modulus and 28.3% increase in shape recovery stress. With the introduction of merely 0.5% of Lys-GO into the PLCL nanofibers, it was found the fiber morphology, tensile properties and shape recovery stress of the GO/PLCL could be largely preserved (>85%). Most importantly, it was demonstrated that the developed Lys-GO/PLCL nanofibers not only enabled to neutralize the acidic degradation products of the PLCL (e.g., the pH acidity was neutralized to 5.2 for the Lys-GO/PCL nanofibers, compared to that of the GO/PLCL counterpart with a pH of 4.2), but also possessed good cytocompatibility and osteogenic differentiation capacity in the rBMSCs. This newly developed shape-memory capable Lys-GO/PLCL fibers may find applications in the construction of multifunctional bone tissue engineering scaffolds.
Graphene oxide (GO) nanosheets with varied mass contents (0%, 0.5%, 1% and 2%) were introduced into the shape memory capable poly(lactide-co-caprolactone) (PLCL) copolymer to prepare GO/PLCL composite nanofibers via electrospinning. Based on the tensile and shape memory properties of the produced GO/PLCL nanofibrous mats, an optimal content of GO (0.5%) was determined to maximize the reinforcing effect of the GO nanosheets to the PLCL fiber matrix. Thereafter, an alkaline amino acid lysine (Lys) was selected to functionalize the GO (0.5%) via EDC/NHS chemistry followed by electrospinning for the generation of multifunctional Lys-GO/PLCL nanofibers. A series of characterization including fiber morphology, mechanical properties, shape memory performance, acidity neutralization capacity and osteogenic differentiation by using the mouse bone mesenchymal stem cells (rBMSCs) were subsequently carried out with the produced Lys-GO/PLCL nanofibers. The results showed that among the four groups of GO/PLCL nanofibers loaded with different GO mass fractions (i.e., 0%, 0.5%, 1% and 2%), incorporation of 0.5% GO within the PLCL nanofibers gave rise to the most remarkable enhancement efficiency, as evidenced by the noted 28.4% increase in Young's modulus and 28.3% increase in shape recovery stress. With the introduction of merely 0.5% of Lys-GO into the PLCL nanofibers, it was found the fiber morphology, tensile properties and shape recovery stress of the GO/PLCL could be largely preserved (>85%). Most importantly, it was demonstrated that the developed Lys-GO/PLCL nanofibers not only enabled to neutralize the acidic degradation products of the PLCL (e.g., the pH acidity was neutralized to 5.2 for the Lys-GO/PCL nanofibers, compared to that of the GO/PLCL counterpart with a pH of 4.2), but also possessed good cytocompatibility and osteogenic differentiation capacity in the rBMSCs. This newly developed shape-memory capable Lys-GO/PLCL fibers may find applications in the construction of multifunctional bone tissue engineering scaffolds.
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2020, 33(3): 207-209.
doi: 10.14133/j.cnki.1008-9357.20200415002
Abstract:
The efficient and controlled construction of hierarchical supramolecular chiral structures has always been the focus and difficulties in the research and application of chiral materials with plenty of challenges. Recently, Prof. Wei Zhang and co-workers at Soochow University proposed polymerization-induced chiral self-assembly (PICSA) concept based on the hydrophobic and liquid-crystalline azobenzene polymer for the first time, by which hierarchical supramolecular chiral polymer assemblies were constructed in a controlled manner. During PICSA process, the internal azobenzene liquid-crystalline ordering, supramolecular interaction and self-assembly of the amphiphilic block copolymers occurred simultaneously, providing an efficient strategy for controlled construction of hierarchical supramolecular chiral polymer assemblies. The molecular-level chirality in polymer systems will be deduced into a higher-level supramolecular chirality and even micro-helix in situ by PICSA strategy. The strategy overcomes the shortcomings of tedious and time-consuming of traditional supramolecular assembly in solution systems.
The efficient and controlled construction of hierarchical supramolecular chiral structures has always been the focus and difficulties in the research and application of chiral materials with plenty of challenges. Recently, Prof. Wei Zhang and co-workers at Soochow University proposed polymerization-induced chiral self-assembly (PICSA) concept based on the hydrophobic and liquid-crystalline azobenzene polymer for the first time, by which hierarchical supramolecular chiral polymer assemblies were constructed in a controlled manner. During PICSA process, the internal azobenzene liquid-crystalline ordering, supramolecular interaction and self-assembly of the amphiphilic block copolymers occurred simultaneously, providing an efficient strategy for controlled construction of hierarchical supramolecular chiral polymer assemblies. The molecular-level chirality in polymer systems will be deduced into a higher-level supramolecular chirality and even micro-helix in situ by PICSA strategy. The strategy overcomes the shortcomings of tedious and time-consuming of traditional supramolecular assembly in solution systems.
2020, 33(3): 210-225.
doi: 10.14133/j.cnki.1008-9357.20190712002
Abstract:
Traditional phase inversion process mainly involves the pore structure regulation of polymeric membranes via controlling the kinetics and thermodynamics, which is a typical physical process, rarely regulating membrane surface/interface properties. However, the surface/interface properties, such as anti-fouling, anti-bacterial and non-clotting performances, influence the separation performances substantially. We propose a “chemical phase inversion” in this paper, which endows the membrane with specific chemical functional surfaces/interfaces during phase inversion process. The key point is to manipulate the migrating route and fixing configuration of funcntional molecules during phase inversion process to accomplish the surface/interface functionalization of polymeric membranes. We summarize the surface/interface functionalization strategies through “chemical phase inversion”, which can be classfied into, the inside-out migration and in-situ cross-linking functionalization strategy based on casting solution, the outside-in migration and off-site cross-linking functionalization strategy based on coagulation bath, and the top-down migration and interfacial cross-linking functionalization strategy based on microporous membranes. According to the differences of the modifiers and the post-treatment process, the membrane can be endowed with excellent anti-fouling, anti-bacterial and non-clotting performances, respectively. The strategies are utilized to modify the microporous membranes for water treatment, oil/water separation and hemodialysis etc. Therefore, the theory of “chemical phase inversion” provides a new research idea for the preparation and separation of high-performance and multifunctional polymeric microporous membranes. However, the introduction of modifiers will also have an impact on phase inversion process, thereby affecting membrane microporous structures. We will further improve the “chemical phase inversion” theory from the view of microporous structure regulation and surface functionalization in later researches.
Traditional phase inversion process mainly involves the pore structure regulation of polymeric membranes via controlling the kinetics and thermodynamics, which is a typical physical process, rarely regulating membrane surface/interface properties. However, the surface/interface properties, such as anti-fouling, anti-bacterial and non-clotting performances, influence the separation performances substantially. We propose a “chemical phase inversion” in this paper, which endows the membrane with specific chemical functional surfaces/interfaces during phase inversion process. The key point is to manipulate the migrating route and fixing configuration of funcntional molecules during phase inversion process to accomplish the surface/interface functionalization of polymeric membranes. We summarize the surface/interface functionalization strategies through “chemical phase inversion”, which can be classfied into, the inside-out migration and in-situ cross-linking functionalization strategy based on casting solution, the outside-in migration and off-site cross-linking functionalization strategy based on coagulation bath, and the top-down migration and interfacial cross-linking functionalization strategy based on microporous membranes. According to the differences of the modifiers and the post-treatment process, the membrane can be endowed with excellent anti-fouling, anti-bacterial and non-clotting performances, respectively. The strategies are utilized to modify the microporous membranes for water treatment, oil/water separation and hemodialysis etc. Therefore, the theory of “chemical phase inversion” provides a new research idea for the preparation and separation of high-performance and multifunctional polymeric microporous membranes. However, the introduction of modifiers will also have an impact on phase inversion process, thereby affecting membrane microporous structures. We will further improve the “chemical phase inversion” theory from the view of microporous structure regulation and surface functionalization in later researches.
2020, 33(3): 226-244.
doi: 10.14133/j.cnki.1008-9357.20190628001
Abstract:
Chemical weapons were applied on a large scale for the first time in World War I. In its continuous development, chemical weapons showed such characteristics as wide killing range, long killing time, multiple poisoning route and low manufacturing cost, which caused a major threat to national security and social stability, thus aroused the general attention of military scientists. From traditional chemical weapons to non-traditional chemical threats such as secondary chemical disasters and chemical terror, chemical protective clothing has always been important equipment to resist these threats. After the development of nearly a century, chemical protective clothing has formed a series mainly composed of air-impermeable and air-permeable type. With the constant development of the threat situation towards stealth variation, it is urgent to make breakthroughs in the principle of protection and new materials, so as to realize the comprehensive improvement of the broad-spectrum protection ability and physiological comfort of chemical protective clothing. Recently, a new type of chemical protective clothing called selectively permeable type came into being and caused wide attention. This kind of protective clothing has excellent comprehensive performance, whose core is selectively permeable material. This selectively permeable material can make a reliable barrier against toxic chemical agents and an efficient transmission of water vapor. According to the different types and mechanisms of selectively permeable materials, this paper reviews the materials based on the ion exchange membranes, carbon-based polymer composites, metal-organic frameworks (MOFs) polymer composites, the polyoxometallates (POMs) polymer composites, decontamination functional polymers, and introduces the protection, decontamination, moisture permeability, and other properties.
Chemical weapons were applied on a large scale for the first time in World War I. In its continuous development, chemical weapons showed such characteristics as wide killing range, long killing time, multiple poisoning route and low manufacturing cost, which caused a major threat to national security and social stability, thus aroused the general attention of military scientists. From traditional chemical weapons to non-traditional chemical threats such as secondary chemical disasters and chemical terror, chemical protective clothing has always been important equipment to resist these threats. After the development of nearly a century, chemical protective clothing has formed a series mainly composed of air-impermeable and air-permeable type. With the constant development of the threat situation towards stealth variation, it is urgent to make breakthroughs in the principle of protection and new materials, so as to realize the comprehensive improvement of the broad-spectrum protection ability and physiological comfort of chemical protective clothing. Recently, a new type of chemical protective clothing called selectively permeable type came into being and caused wide attention. This kind of protective clothing has excellent comprehensive performance, whose core is selectively permeable material. This selectively permeable material can make a reliable barrier against toxic chemical agents and an efficient transmission of water vapor. According to the different types and mechanisms of selectively permeable materials, this paper reviews the materials based on the ion exchange membranes, carbon-based polymer composites, metal-organic frameworks (MOFs) polymer composites, the polyoxometallates (POMs) polymer composites, decontamination functional polymers, and introduces the protection, decontamination, moisture permeability, and other properties.
2020, 33(3): 245-252.
doi: 10.14133/j.cnki.1008-9357.20190424001
Abstract:
Virus-like particles (VLPs) have attracted increasing attentions in the field of drug-delivery.The ordered surface nanostructure is one of the essential structures of the natural virus. The preparation and drug-loading property of polypeptide-based hollow VLPs with ordered surface nanostructures were investigated. Starting from poly(γ-benzyl-L-glutamate)-block-poly(ethylene glycol) (PBLG-b-PEG) block copolymers, through deprotection of the benzyl group and subsequent esterification reaction, poly(γ-benzyl-L-glutamate-co-γ-cinnamyl-L-glutamate) -block-poly(ethylene glycol) (P(BLG/CLG)-b-PEG) block copolymers were synthesized, in which the cinnamyl group was photo-cross-linkable. The photo-cross-linking process of the P(BLG/CLG)-b-PEG block copolymers was tracked by the UV-Vis spectrum. Adding water to the solution of P(BLG/CLG)-b-PEG block copolymer and PS homopolymers in THF-DMF mixture (volume ratio 1/1), spherical VLPs were self-assembled from the polymer mixtures. These VLPs contained a PS homopolymer core and P(BLG/CLG)-b-PEG block copolymer shell, and the P(BLG/CLG)-b-PEG block copolymers packed orderly forming strips on the surface. When replacing the PS homopolymers by rigid PBLG homopolymers, rod-like VLPs were obtained in which the PBLG homopolymers formed bundles and P(BLG/CLG)-b-PEG block copolymers self-assembled on the surface of the PBLG homopolymer bundles into helical nanostructures. Under UV-irradiation at λ = 254 nm, the P(BLG/CLG) blocks in the shell of both the spherical and the rod-like VLPs were cross-linked through the photodimerization of the cinnamyloxy groups. To the solution of the shell-crosslinked spherical VLPs, adding a large amount of DMF could remove the PS core-forming hollow virus-like particles (HVLPs), and the strip patterns on the surface were retained. However, for the rod-like VLPs, under similar conditions, the PBLG homopolymers in the core could not be removed. The drug-loading capacity of the spherical HVLPs was evaluated by using doxorubicin (DOX) as a model drug. It was found that DOX was successfully loaded into the HVLPs with a high relative drug-loading mass fraction (230%). Releasing studies revealed that the drugs could gradually release from the VLPs, and 72 h accumulate releasing mass fraction reached about 80%. This work provides a method to prepare polypeptide-based HVLPs with surface nanostructures, and these HVLPs could find applications for drug delivery.
Virus-like particles (VLPs) have attracted increasing attentions in the field of drug-delivery.The ordered surface nanostructure is one of the essential structures of the natural virus. The preparation and drug-loading property of polypeptide-based hollow VLPs with ordered surface nanostructures were investigated. Starting from poly(γ-benzyl-L-glutamate)-block-poly(ethylene glycol) (PBLG-b-PEG) block copolymers, through deprotection of the benzyl group and subsequent esterification reaction, poly(γ-benzyl-L-glutamate-co-γ-cinnamyl-L-glutamate) -block-poly(ethylene glycol) (P(BLG/CLG)-b-PEG) block copolymers were synthesized, in which the cinnamyl group was photo-cross-linkable. The photo-cross-linking process of the P(BLG/CLG)-b-PEG block copolymers was tracked by the UV-Vis spectrum. Adding water to the solution of P(BLG/CLG)-b-PEG block copolymer and PS homopolymers in THF-DMF mixture (volume ratio 1/1), spherical VLPs were self-assembled from the polymer mixtures. These VLPs contained a PS homopolymer core and P(BLG/CLG)-b-PEG block copolymer shell, and the P(BLG/CLG)-b-PEG block copolymers packed orderly forming strips on the surface. When replacing the PS homopolymers by rigid PBLG homopolymers, rod-like VLPs were obtained in which the PBLG homopolymers formed bundles and P(BLG/CLG)-b-PEG block copolymers self-assembled on the surface of the PBLG homopolymer bundles into helical nanostructures. Under UV-irradiation at λ = 254 nm, the P(BLG/CLG) blocks in the shell of both the spherical and the rod-like VLPs were cross-linked through the photodimerization of the cinnamyloxy groups. To the solution of the shell-crosslinked spherical VLPs, adding a large amount of DMF could remove the PS core-forming hollow virus-like particles (HVLPs), and the strip patterns on the surface were retained. However, for the rod-like VLPs, under similar conditions, the PBLG homopolymers in the core could not be removed. The drug-loading capacity of the spherical HVLPs was evaluated by using doxorubicin (DOX) as a model drug. It was found that DOX was successfully loaded into the HVLPs with a high relative drug-loading mass fraction (230%). Releasing studies revealed that the drugs could gradually release from the VLPs, and 72 h accumulate releasing mass fraction reached about 80%. This work provides a method to prepare polypeptide-based HVLPs with surface nanostructures, and these HVLPs could find applications for drug delivery.
2020, 33(3): 253-261.
doi: 10.14133/j.cnki.1008-9357.20190530001
Abstract:
Based on a non-planar fused perylene diimide unit (FPDI-Th), a new class of polymers, PPDIBT-Th and PPDIBT-Th-C6, were designed and synthesized, and they were served as acceptors for application in all-polymer solar cells. Compared to PPDIBT-Th, hexyl side chain was introduced into PPDIBT-Th-C6 to tune the molecular conformation. These two polymers as well as the fabrication and measurement of all-polymer solar cell devices were systematically studied by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), UV-Vis absorption and cyclic voltammetry (CV). Both of devices blending PPDIBT-Th or PPDIBT-Th-C6 with polymer donor PTB7-Th show good photovoltaic performances, indicating that the polymers contained FPDI-Th are promising acceptors for all-polymer solar cells. In addition, the introduction of side chains into the polymers decreases the planarity of the backbones, leading to a weaker molecular packing and absorption intensity. However, the side chains not only affect the properties of acceptor itself but also tune the molecular packing of polymer donor that is another component in bulk heterojunction (BHJ). In the blend film, PPDIBT-Th with strong intermolecular interaction inhibits the aggregation of donor PTB7-Th, leading to an inferior morphology which has been verified by the device performances and atomic force microscopy (AFM) characterization. Due to the balance between miscibility and crystallinity, all-polymer solar cells based on PPDIBT-Th-C6 and PTB7-Th display a higher short-circuit current density (Jsc) of 12.15 mA/cm2, eventually achieving a superior power conversion efficiency (PCE) of 4.95%.
Based on a non-planar fused perylene diimide unit (FPDI-Th), a new class of polymers, PPDIBT-Th and PPDIBT-Th-C6, were designed and synthesized, and they were served as acceptors for application in all-polymer solar cells. Compared to PPDIBT-Th, hexyl side chain was introduced into PPDIBT-Th-C6 to tune the molecular conformation. These two polymers as well as the fabrication and measurement of all-polymer solar cell devices were systematically studied by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), UV-Vis absorption and cyclic voltammetry (CV). Both of devices blending PPDIBT-Th or PPDIBT-Th-C6 with polymer donor PTB7-Th show good photovoltaic performances, indicating that the polymers contained FPDI-Th are promising acceptors for all-polymer solar cells. In addition, the introduction of side chains into the polymers decreases the planarity of the backbones, leading to a weaker molecular packing and absorption intensity. However, the side chains not only affect the properties of acceptor itself but also tune the molecular packing of polymer donor that is another component in bulk heterojunction (BHJ). In the blend film, PPDIBT-Th with strong intermolecular interaction inhibits the aggregation of donor PTB7-Th, leading to an inferior morphology which has been verified by the device performances and atomic force microscopy (AFM) characterization. Due to the balance between miscibility and crystallinity, all-polymer solar cells based on PPDIBT-Th-C6 and PTB7-Th display a higher short-circuit current density (Jsc) of 12.15 mA/cm2, eventually achieving a superior power conversion efficiency (PCE) of 4.95%.
2020, 33(3): 262-268.
doi: 10.14133/j.cnki.1008-9357.20190424002
Abstract:
Graphene is a zero-gap semiconductor with low work function and high leakage current which limit its applications. Doping of nitrogen is one of the ways to tailor the properties of graphene. However, there remain some defects, such as the low nitrogen content and poor controllability. In order to enhance the content of nitrogen and control the bonding characters to embed nitrogen atoms inside the carbon lattice, solid-state sources (melamine) and gas-state sources (methane) were used to prepare nitrogen doped graphene (NG) films. The preparation time, the dosage of melamine and temperature were set as tunable parameters. The morphology of NG, the content of nitrogen (mass fraction of nitrogen atoms) and the bonding characters for the embedding of N atoms were studied. The results indicated that the preparation process of NG films was involved with nucleation, growth and aggregation. Proper temperature (990 ℃) was conductive for the improvement of the content of nitrogen. Pyrrolic N was produced at high temperature (＞1 000 ℃), while graphitic N was on the opposite. With increasing the dosage of melamine, the content of nitrogen was increased and then decreased with the maximum value of 6.98%. The content of Pyridinic N will be elevated with increasing the amount of melamine. Compared with graphene, NG films were capable of detecting the Raman signals from Rhodamine B molecules even at the concentration as low as 10−5 mol/L.
Graphene is a zero-gap semiconductor with low work function and high leakage current which limit its applications. Doping of nitrogen is one of the ways to tailor the properties of graphene. However, there remain some defects, such as the low nitrogen content and poor controllability. In order to enhance the content of nitrogen and control the bonding characters to embed nitrogen atoms inside the carbon lattice, solid-state sources (melamine) and gas-state sources (methane) were used to prepare nitrogen doped graphene (NG) films. The preparation time, the dosage of melamine and temperature were set as tunable parameters. The morphology of NG, the content of nitrogen (mass fraction of nitrogen atoms) and the bonding characters for the embedding of N atoms were studied. The results indicated that the preparation process of NG films was involved with nucleation, growth and aggregation. Proper temperature (990 ℃) was conductive for the improvement of the content of nitrogen. Pyrrolic N was produced at high temperature (＞1 000 ℃), while graphitic N was on the opposite. With increasing the dosage of melamine, the content of nitrogen was increased and then decreased with the maximum value of 6.98%. The content of Pyridinic N will be elevated with increasing the amount of melamine. Compared with graphene, NG films were capable of detecting the Raman signals from Rhodamine B molecules even at the concentration as low as 10−5 mol/L.
2020, 33(3): 269-274.
doi: 10.14133/j.cnki.1008-9357.20190429003
Abstract:
DNA-functionalized nanoparticles, regarded as the programmable atom equivalent, enable the realization of hierarchically self-assembled superstructures. The self-assembled superstructures possessing unique mechanic, optical and electronic properties have prospective applications in the field of energy conservation, catalysis and medical diagnostics. With the development of nanotechnology, non-uniformly DNA-functionalized nanoparticles with DNA strands regioselectively distributed on the surfaces have been successfully synthesized. Recently, by utilizing the non-uniformly DNA-functionalized nanoparticles, researchers have created nanoparticle superstructures with complex architecture in the lab, such as discrete planet-satellite nanostructures, one-dimensional nanoparticle chains, and even three-dimensional networks. However, the mechanism and design rules of self-assembly of non-uniformly DNA-functionalized nanoparticles remain to be explored. Herein, the coarse-grained model of non-uniformly DNA-functionalized nanoparticles is constructed, and molecular dynamics is utilized to simulate the self-assembly process of DNA-programmable nanoparticles. It is demonstrated that the non-uniformly DNA-functionalized nanoparticles self-assemble into branched or even network-like superstructures through the hybridization of complementary DNA strands. The geometrical model of self-assembled superstructures is proposed to predict the relative position and distribution of nanoparticles inside the superstructures. Sparked by the molecular polymerization, we further explored the effect of stoichiometric ratio on the self-assembly of nanoparticles. The stoichiometric ratio of nanoparticles has remarkable effects on both the architecture of superstructures and the kinetics of DNA-programmable self-assembly of nanoparticles. As the stoichiometric ratio increased from 1.0 to 5.7, the self-assembled superstructures switch from the spanning networks to discrete branched clusters.
DNA-functionalized nanoparticles, regarded as the programmable atom equivalent, enable the realization of hierarchically self-assembled superstructures. The self-assembled superstructures possessing unique mechanic, optical and electronic properties have prospective applications in the field of energy conservation, catalysis and medical diagnostics. With the development of nanotechnology, non-uniformly DNA-functionalized nanoparticles with DNA strands regioselectively distributed on the surfaces have been successfully synthesized. Recently, by utilizing the non-uniformly DNA-functionalized nanoparticles, researchers have created nanoparticle superstructures with complex architecture in the lab, such as discrete planet-satellite nanostructures, one-dimensional nanoparticle chains, and even three-dimensional networks. However, the mechanism and design rules of self-assembly of non-uniformly DNA-functionalized nanoparticles remain to be explored. Herein, the coarse-grained model of non-uniformly DNA-functionalized nanoparticles is constructed, and molecular dynamics is utilized to simulate the self-assembly process of DNA-programmable nanoparticles. It is demonstrated that the non-uniformly DNA-functionalized nanoparticles self-assemble into branched or even network-like superstructures through the hybridization of complementary DNA strands. The geometrical model of self-assembled superstructures is proposed to predict the relative position and distribution of nanoparticles inside the superstructures. Sparked by the molecular polymerization, we further explored the effect of stoichiometric ratio on the self-assembly of nanoparticles. The stoichiometric ratio of nanoparticles has remarkable effects on both the architecture of superstructures and the kinetics of DNA-programmable self-assembly of nanoparticles. As the stoichiometric ratio increased from 1.0 to 5.7, the self-assembled superstructures switch from the spanning networks to discrete branched clusters.
2020, 33(3): 275-283.
doi: 10.14133/j.cnki.1008-9357.20190424003
Abstract:
Melampomagnolide B (MMB) is one of the parthenolide (PTL) derivatives with high anticancer activity to various tumors. However, its application in the clinic is limited due to its poor water solubility. To overcome this problem, an amphiphilic prodrug is synthesized from carboxyl polyethylene glycol monomethyl ether (mPEG10-COOH) and MMB through an esterification reaction. The chemical structure of mPEG10-MMB is confirmed by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS). The amphiphilic prodrug mPEG10-MMB can self-assemble in water with the critical micelle mass concentration of 7.7 μg/mL and the size/morphology of its assemblies is characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The DLS result indicates that an averaged size of mPEG10-MMB nanoparticles is about 120.3 nm with a narrow distribution. The TEM image exhibits that mPEG10-MMB can self-assemble into spherical nanoparticles with an average diameter of 108.5 nm. Nile red (NR) is used as the fluorescent probe and loaded in mPEG10-MMB prodrug nanoparticles. The flow cytometry and confocal laser scanning microscope (CLSM) are used to evaluate the cell uptake of mPEG10-MMB prodrug nanoparticles. The results demonstrate that mPEG10-MMB prodrug nanoparticles can be internalized by HeLa cells efficiently through the endocytosis mechanism. In vitro cytotoxicity of mPEG10-MMB prodrug nanoparticles is evaluated against HeLa cells and BRL-3A cells by MTT assay. The result demonstrates that mPEG10-MMB prodrug nanoparticles have higher cytotoxicity to cancer cells compared to that of free MMB, but relatively lower cytotoxicity to normal cells.
Melampomagnolide B (MMB) is one of the parthenolide (PTL) derivatives with high anticancer activity to various tumors. However, its application in the clinic is limited due to its poor water solubility. To overcome this problem, an amphiphilic prodrug is synthesized from carboxyl polyethylene glycol monomethyl ether (mPEG10-COOH) and MMB through an esterification reaction. The chemical structure of mPEG10-MMB is confirmed by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS). The amphiphilic prodrug mPEG10-MMB can self-assemble in water with the critical micelle mass concentration of 7.7 μg/mL and the size/morphology of its assemblies is characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The DLS result indicates that an averaged size of mPEG10-MMB nanoparticles is about 120.3 nm with a narrow distribution. The TEM image exhibits that mPEG10-MMB can self-assemble into spherical nanoparticles with an average diameter of 108.5 nm. Nile red (NR) is used as the fluorescent probe and loaded in mPEG10-MMB prodrug nanoparticles. The flow cytometry and confocal laser scanning microscope (CLSM) are used to evaluate the cell uptake of mPEG10-MMB prodrug nanoparticles. The results demonstrate that mPEG10-MMB prodrug nanoparticles can be internalized by HeLa cells efficiently through the endocytosis mechanism. In vitro cytotoxicity of mPEG10-MMB prodrug nanoparticles is evaluated against HeLa cells and BRL-3A cells by MTT assay. The result demonstrates that mPEG10-MMB prodrug nanoparticles have higher cytotoxicity to cancer cells compared to that of free MMB, but relatively lower cytotoxicity to normal cells.
2020, 33(3): 284-289.
doi: 10.14133/j.cnki.1008-9357.20190510001
Abstract:
A kind of hyperbranched azopolymers (HPAzoAMAM) with different structures and molecular weights were successfully synthesized via Michael addition polymerization between A2 and B2B' monomers. All the structures of HPAzoAMAM and their corresponding molecular weights were analyzed. HPAzoAMAM can self-assemble into aggregates with different morphologies and sizes in aqueous solution confirmed by SEM, TEM and DLS. The photo-isomerization of HPAzoAMAM in DMF and micelle solution were both studied through UV-Vis spectrophotometer. The final results showed that the structure of HPAzoAMAM could be modulated by controlling the molar ratio of the initial A2 and B2B' monomers. HPAzoAMAM could self-assemble into large spherical compound micelles (LCMs) with various sizes in aqueous solution because of their different hydrophilicities and molecular weights. With the increasing of the hydrophobicity and molecular weight of HPAzoAMAM, the size of LCMs turned to be larger. The reversible transcis isomerization behavior of HPAzoAMAM in DMF and micelle aqueous solution were studied by UV-Vis irradiation. The results showed that all the absorption peaks of HPAzoAMAM in DMF were at the same positon of 377 nm, while those of the micelle aqueous solutions of HPAzoAMAM-1, HPAzoAMAM-2, HPAzoAMAM-3 were at 376, 367 nm and 372 nm, respectively. Therefore, HPAzoAMAM aggregates were in different π-π stacking styles. Furthermore, in the case of HPAzoAMAM micelle isomerization, the time for reaching stationary state was much longer than that in DMF solution, which was attributed to the highly regular arrangement of azobenzene moieties in aggregates and the restriction of the hyperbranched structures. The feasible combination of azobenzene and hyperbranched polymer provides a promising guidance for the application research of azopolymers.
A kind of hyperbranched azopolymers (HPAzoAMAM) with different structures and molecular weights were successfully synthesized via Michael addition polymerization between A2 and B2B' monomers. All the structures of HPAzoAMAM and their corresponding molecular weights were analyzed. HPAzoAMAM can self-assemble into aggregates with different morphologies and sizes in aqueous solution confirmed by SEM, TEM and DLS. The photo-isomerization of HPAzoAMAM in DMF and micelle solution were both studied through UV-Vis spectrophotometer. The final results showed that the structure of HPAzoAMAM could be modulated by controlling the molar ratio of the initial A2 and B2B' monomers. HPAzoAMAM could self-assemble into large spherical compound micelles (LCMs) with various sizes in aqueous solution because of their different hydrophilicities and molecular weights. With the increasing of the hydrophobicity and molecular weight of HPAzoAMAM, the size of LCMs turned to be larger. The reversible transcis isomerization behavior of HPAzoAMAM in DMF and micelle aqueous solution were studied by UV-Vis irradiation. The results showed that all the absorption peaks of HPAzoAMAM in DMF were at the same positon of 377 nm, while those of the micelle aqueous solutions of HPAzoAMAM-1, HPAzoAMAM-2, HPAzoAMAM-3 were at 376, 367 nm and 372 nm, respectively. Therefore, HPAzoAMAM aggregates were in different π-π stacking styles. Furthermore, in the case of HPAzoAMAM micelle isomerization, the time for reaching stationary state was much longer than that in DMF solution, which was attributed to the highly regular arrangement of azobenzene moieties in aggregates and the restriction of the hyperbranched structures. The feasible combination of azobenzene and hyperbranched polymer provides a promising guidance for the application research of azopolymers.
2020, 33(3): 290-296.
doi: 10.14133/j.cnki.1008-9357.20190312001
Abstract:
The influence of catalyst and CO2 on the synthesis of bio-based poly(γ-aminobutyric acid) (PGABA) was investigated in the presence of an acyl compound initiator. The molecular structure and crystal form of the products were examined using magnetic resonance spectroscopy (1H-NMR), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD). Thermogravimetry (TG) and differential scanning calorimetry (DSC) were used to evaluate the thermal properties of PGABA prepared via different ways. Results indicated that the addition of CO2 had an adverse effect on the yield of PGABA. When the mole fraction of acyl catalyst was fixed at 6% or 7%, the molecular weight increased at first and then decreased with increasing the dosage of CO2 , while the yield decreased successively. When the mole fraction of catalyst was increased to 9%, increasing the dosage of CO2 less affected the molecular weight of PGABA, but the yield kept decreasing. On the other hand, the absence of the initiator dramatically decreased the yield of PGABA in the CO2 containing system. At the different dosages of CO2, the molecular weight rose firstly and then went down with increasing catalyst mole fraction. Such a trend became not evidence at a high dosage of CO2. The impact of catalyst mole fraction on the yield was a little complex. The yield could reach a maximum with increasing the catalyst mole fraction when CO2 mole fraction was less than 13.2%, above which a positive effect of the catalyst on the yield was presented. The crystals of PGABA samples prepared through various methods were all of the α form and independent of the mole fraction of catalyst, initiator, and CO2. Moreover, introducing CO2 less affected the melting point of PGABA, but led to the increase of the thermal decomposition temperature and the improvement of the thermal stability of PGABA.
The influence of catalyst and CO2 on the synthesis of bio-based poly(γ-aminobutyric acid) (PGABA) was investigated in the presence of an acyl compound initiator. The molecular structure and crystal form of the products were examined using magnetic resonance spectroscopy (1H-NMR), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD). Thermogravimetry (TG) and differential scanning calorimetry (DSC) were used to evaluate the thermal properties of PGABA prepared via different ways. Results indicated that the addition of CO2 had an adverse effect on the yield of PGABA. When the mole fraction of acyl catalyst was fixed at 6% or 7%, the molecular weight increased at first and then decreased with increasing the dosage of CO2 , while the yield decreased successively. When the mole fraction of catalyst was increased to 9%, increasing the dosage of CO2 less affected the molecular weight of PGABA, but the yield kept decreasing. On the other hand, the absence of the initiator dramatically decreased the yield of PGABA in the CO2 containing system. At the different dosages of CO2, the molecular weight rose firstly and then went down with increasing catalyst mole fraction. Such a trend became not evidence at a high dosage of CO2. The impact of catalyst mole fraction on the yield was a little complex. The yield could reach a maximum with increasing the catalyst mole fraction when CO2 mole fraction was less than 13.2%, above which a positive effect of the catalyst on the yield was presented. The crystals of PGABA samples prepared through various methods were all of the α form and independent of the mole fraction of catalyst, initiator, and CO2. Moreover, introducing CO2 less affected the melting point of PGABA, but led to the increase of the thermal decomposition temperature and the improvement of the thermal stability of PGABA.
2020, 33(3): 297-304.
doi: 10.14133/j.cnki.1008-9357.20190415002
Abstract:
A series of new bactericidal alginate calcium-copper nanoparticle nanocomposite films, denoted by Ca2+-Alg-Cu, were prepared by electrophoretic deposition with the constant current mode, by adjusting the copper nanoparticle composition in the electrolyte. According to the content of copper nanoparticles in the final formed film, they were denoted by Ca2+-Alg-Cu10, Ca2+-Alg-Cu20, and Ca2+-Alg-Cu50, respectively. The existence of copper nanoparticles in the nanocomposite films was confirmed via scanning electron microscopy (SEM), energy dispersive spectrometer (EPS), and Fourier-transformed infrared spectroscopy (FT-IR). Three different common infectious bacteria, including E. coli., S. aureus and P. aeruginosa, were taken as infectious pathogen models to explore the bactericidal property of Ca2+-Alg-Cu by plate counting method for 24 h. In addition, external animal skin cells such as mice L929 fibroblasts were incubated with Ca2+-Alg-Cu to assess the in vitro biocompatibility. Results show that Ca2+-Alg-Cu can potentially kill the three representative bacteria species by inducing cellular exterior membrane deformation and wrinkling, which is the inferred way of destruction in cellular structure. The potency of Ca2+-Alg-Cu depends on the mass fraction of copper nanoparticles (Cu) in the electrolyte. More efficiency can be obtained with higher content of copper nanoparticles, as can be seen in the experimental result. When the mass concentration of Cu in the electrolyte is lower than 0.4 mg/mL, the cellular viability is higher than 80%. Overall, it is indicated that a balanced antimicrobial activity and in vitro biocompatibility to the animal skin extracted cells can be realized.
A series of new bactericidal alginate calcium-copper nanoparticle nanocomposite films, denoted by Ca2+-Alg-Cu, were prepared by electrophoretic deposition with the constant current mode, by adjusting the copper nanoparticle composition in the electrolyte. According to the content of copper nanoparticles in the final formed film, they were denoted by Ca2+-Alg-Cu10, Ca2+-Alg-Cu20, and Ca2+-Alg-Cu50, respectively. The existence of copper nanoparticles in the nanocomposite films was confirmed via scanning electron microscopy (SEM), energy dispersive spectrometer (EPS), and Fourier-transformed infrared spectroscopy (FT-IR). Three different common infectious bacteria, including E. coli., S. aureus and P. aeruginosa, were taken as infectious pathogen models to explore the bactericidal property of Ca2+-Alg-Cu by plate counting method for 24 h. In addition, external animal skin cells such as mice L929 fibroblasts were incubated with Ca2+-Alg-Cu to assess the in vitro biocompatibility. Results show that Ca2+-Alg-Cu can potentially kill the three representative bacteria species by inducing cellular exterior membrane deformation and wrinkling, which is the inferred way of destruction in cellular structure. The potency of Ca2+-Alg-Cu depends on the mass fraction of copper nanoparticles (Cu) in the electrolyte. More efficiency can be obtained with higher content of copper nanoparticles, as can be seen in the experimental result. When the mass concentration of Cu in the electrolyte is lower than 0.4 mg/mL, the cellular viability is higher than 80%. Overall, it is indicated that a balanced antimicrobial activity and in vitro biocompatibility to the animal skin extracted cells can be realized.
2020, 33(3): 305-312.
doi: 10.14133/j.cnki.1008-9357.20190430002
Abstract:
Poly(sarcosine-co-glutamate hydrazide) (P(Sar-co-GH)) with good water solubility and hydrazide group and oxidized sodium alginate (OSA) with aldehyde group were designed and prepared. Under mild conditions, hydrogels composed of P(Sar-co-GH), OSA and carboxymethyl chitosan (CMC) could be prepared based on acylhydrazone bonds formed between P(Sar-co-GH) and OSA and imine bonds formed between CMC and OSA. The structure and mechanical properties of the hydrogels were characterized by FT-IR and rotational rheometer. Results show that the mechanical properties of hydrogels can be adjusted from 840 Pa to 5 690 Pa by changing the content of P(Sar-co-GH) and CMC. The double dynamic chemical bond hydrogel can be injected by the 23 G needle and also exhibit the self-healing behavior within 12 h. Moreover, the hydrogels can undergo repeated gel-sol transition under the regulation of triethylamine(TEA) and hydrochloric acid(HCl). In vitro cytotoxicity and cell culture experiments demonstrate that copolymer and hydrogel extract are nontoxic to mouse embryonic cells（NIH/3T3） and can support NIH/3T3 growth and proliferation. Overall, a new hydrogel based on polypeptide and polysaccharide is developed by dual dynamic covalent bond, which endows the material with injectability, self-healing properties and pH responsiveness and has great potential in biomedical field.
Poly(sarcosine-co-glutamate hydrazide) (P(Sar-co-GH)) with good water solubility and hydrazide group and oxidized sodium alginate (OSA) with aldehyde group were designed and prepared. Under mild conditions, hydrogels composed of P(Sar-co-GH), OSA and carboxymethyl chitosan (CMC) could be prepared based on acylhydrazone bonds formed between P(Sar-co-GH) and OSA and imine bonds formed between CMC and OSA. The structure and mechanical properties of the hydrogels were characterized by FT-IR and rotational rheometer. Results show that the mechanical properties of hydrogels can be adjusted from 840 Pa to 5 690 Pa by changing the content of P(Sar-co-GH) and CMC. The double dynamic chemical bond hydrogel can be injected by the 23 G needle and also exhibit the self-healing behavior within 12 h. Moreover, the hydrogels can undergo repeated gel-sol transition under the regulation of triethylamine(TEA) and hydrochloric acid(HCl). In vitro cytotoxicity and cell culture experiments demonstrate that copolymer and hydrogel extract are nontoxic to mouse embryonic cells（NIH/3T3） and can support NIH/3T3 growth and proliferation. Overall, a new hydrogel based on polypeptide and polysaccharide is developed by dual dynamic covalent bond, which endows the material with injectability, self-healing properties and pH responsiveness and has great potential in biomedical field.
Accepted
Chinese Library Classification 