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Construction and Performance of Proanthocyanidin Enhanced PEG-Lysozyme Bioactive Hydrogel Dressing
CHEN Zhanyi, TAN Haoqi, QU Xue
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.2020062001
[Abstract](0) [FullText HTML](0) [PDF 748KB](0)
The proanthocyanidin (PC)-enhanced polyethylene glycol (PEG)-lysozyme (LZM) hydrogel (PEG-LZM-PC) was prepared based on PEG-LZM hydrogel by post-soaking with PC. The morphology, structure and mechanical properties of PEG-LZM-PC were assessed by scanning electron microscope (SEM), Fourier-transformed infrared (FT-IR) spectroscopy and universal testing instruments, the antibacterial ability of PEG-ZEM-PC was evaluated by plate coating method, and the effect of PEG-LZM-PC on the expression of inflammatory factors in immune cells was evaluated by quantitative reverse transcription PCR (RT-qPCR). The results show that the strength and toughness of PEG-LZM-PC are significantly improved compared with PEG-LZM, the antibacterial performance of PEG-LZM-PC in vivo and in vitro is pretty good, and the inflammatory response caused by lipopolysaccharide (LPS) stimulation is inhibited by PEG-LZM-PC, which is expected to promote wound healing.
Synthesis and Photocatalytic Hydrogen Evolution Study of Triazine-Based Conjugated Microporous Polymers
YANG Guang, WANG Qian, LI Qingyin, REN Shijie
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20200810001
[Abstract](1) [FullText HTML](1) [PDF 1125KB](0)
Photocatalytic water splitting to produce hydrogen is one of the effective ways to achieve solar energy utilization, in which the key point is to develop efficient and cheap photocatalysts. Conjugated microporous polymers (CMPs), allowing the fine synthetic control over their chemical structures and electronic properties, have become a new type of photocatalysts due to their diverse synthetic modularity. In order to investigate the effects of molecular structures on the photocatalytic performance of CMPs, four triazine-based conjugated microporous polymers (TCMPs) were designed and synthesized by Suzuki coupling reaction in this work, among which, TTCMP1 and TTCMP2 contain thiophene units, and TFCMP1 and TFCMP2 possess fluorene units. These TCMPs have high specific surface areas and appropriate optical band gaps. Through optical analysis of these TCMPs, it is found that the structural change of functional units and the length of linkers can tune the energy band gap, thereby influencing the hydrogen production performance of the polymers. Results show that TFCMPs containing fluorene units show better photocatalytic hydrogen production performance. And TFCMP2 with longer linking units shows the highest hydrogen release rate of 244 μmol·h−1·g−1 under visible light (λ ≥ 420 nm). This work provides a promising strategy for exploring the relationship between the structure and performance of CMPs for photocatalytic hydrogen evolution.
Cross-Linked Ethylene/Propylene Copolymer Based on Reversible Dynamic Covalent Chemistry
LIU Shuhui, NIU Hui
 doi: 10.14133/j.cnki.1008-9357.20200611002
[Abstract](110) [FullText HTML](52) [PDF 1123KB](18)
The ternary copolymerization of ethylene/propene/8-furyl-1-octene was conducted with metallocene rac-Et(Ind)2ZrCl2 as the catalyst and methylaluminoxane (MAO) as the cocatalyst to synthesize the ethylene/propylene copolymer with furyl-side groups. The copolymerization was proved to be of high efficiency with controllable copolymer composition. The copolymer structures were characterized by 1H-NMR, DSC and GPC. Ethylene/propylene copolymers with thermoreversible cross-linking structure were prepared via Diels-Alder reaction using different bismaleimide molecules, that is, with –C6H4(CH2)C6H4―, ―(CH2)6―, and ―(CH2)12– as the middle segment of bismaleimide which were named as Ph2, C6, and C12, respectively, as the cross-linking agent. The cross-linking degree was determined quantitatively by equilibrium swelling measurements, and the properties of the cross-linked materials were determined by tensile test. Results showed that the cross-linking degree of copolymers could be controlled by changing the structure of cross-linking agent and adjusting the mole ratio of maleimide to furan. The cross-linking degree of the materials prepared by flexible bismaleimides C6 and C12 was more stable. Whereas for the cross-linked specimens obtained from rigid Ph2, the gel content and swelling ratio changed significantly after repeated processing. When bismaleimide was sub-stoichiometric, the cross-linking reaction could be fully implemented, so as to ensure the stability of cross-linking degree of the sample after repeated processing. The flexibility of the cross-linking agent could also promote the cross-linking reaction. In summary, the thermal reversibility of the Diels-Alder rings formed between the maleimide and furan groups rendered the cross-linked materials with repeatable processability.
Preparation and Drug Delivery of pH-Sensitive Polymeric Micelles mPEG-GDE-OE
SUN Hui, WANG Fei, WANG Yunyun, GONG Kai
 doi: 10.14133/j.cnki.1008-9357.20200313002
[Abstract](589) [FullText HTML](311) [PDF 6903KB](13)
An orthoester monomer of (2-(octadecyloxy)-1,3-dioxolan-4-yl) methanamine (OE) was synthesized using 3-amino-1,2-propanediol as starting material. A novel pH-sensitive polymer, mPEG-GDE-OE, was prepared by ring opening polymerization of OE, methoxypolyethylene glycol amine (mPEG-NH2) and glycol diglycidyl ether (GDE). The pH-insensitive polymer, mPEG-GDE-OA, was synthesized as a reference polymer. Amphiphilic polymers (mPEG-GDE-OE and mPEG-GDE-OA) could self-assemble into micelles by solvent volatilization method. Then doxorubicin (DOX) was used as a model drug to incorporate into mPEG-GDE-OE and mPEG-GDE-OA micelles. These polymers were characterized by 1H-NMR. The size and the morphologies of the micelles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The drug release properties of micelles were investigated in vitro. Human breast cancer cells (MCF-7) and cervical cancer cells (Hela) were used as model tumor cell lines to investigate the cytotoxicity and antitumor activity of drug loaded polymer micelles in vitro. Results show that the particle sizes of mPEG-GDE-OE and mPEG-GDE-OA micelles are (168.2 ± 4.6) nm and (157.5 ± 3.4) nm, respectively. The particle sizes of drug-loaded micelles, DOX/mPEG-GDE-OE and DOX/mPEG-GDE-OA, are (191.6±6.7) nm and (182.8±5.2) nm, respectively. Compared with mPEG-GDE-OA micelles, mPEG-GDE-OE micelles have good pH sensitivity, good controlled release performance and strong tumor killing ability.
CO2-Based Hyperbranched Poly(alkynoate)s: A Platform Polymer for Diverse Functionalizations
ZHANG Xinghong
 doi: 10.14133/j.cnki.1008-9357.20200830001
[Abstract](109) [FullText HTML](76) [PDF 732KB](2)
As an abundant, nontoxic and inexpensive one-carbon (C1) feedstock, carbon dioxide (CO2) has been used as the monomer for preparing a variety of polymers via copolymerization process, such as polycarbonates, poly(urethane)s and polyureas that are linear chain structure. Due to the limit in designing multi-functionalized comonomers, using CO2 to synthesize polymers with different architectures, such as hyperbranched polymers (HBPs), is rarely reported. Recently, Qin and Tang et al. have reported a successful synthesis of CO2-based hyperbranched poly(alkynoate)s (hb-PAs) via three-component polymerization of CO2, multi-functionalized alkyne and dihalides under mild conditions. The resultant polymer possessed two types of ethynyl groups with different reactivities towards the same types of amines, so it could undergo site-selective, multi-step functionalizations. Taking advantage of this facile and efficient site-selective functionalization strategy, they prepared a hyperbranched polyprodrug amphiphile with high drug loading content, an artificial light-harvesting system with high energy transfer efficiency and pure white light-emitting polymeric materials. This work provides a new method to convert CO2 into multifunctional HBPs that are platform polymers for diverse functionalizations.
A Novel Oral Drug Delivery Carrier Based on Polylactide-Polyhistidine
YI Cuicui, MA Mengya, WU Chaohui, WANG Jinfeng, ZHANG Zhenzhong, REN Xueling
 doi: 10.14133/j.cnki.1008-9357.20200403001
[Abstract](104) [FullText HTML](73) [PDF 1308KB](9)
Firstly, polyhistidine (PLH) was synthesized by ring-opening polymerization of anhydride, and then condensed with polylactide (PLA) to form an amphiphilic block copolymer (PLA-PLH). Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance hydrogen spectroscopy (1H-NMR) and dynamic light scattering (DLS) were used to characterize the structure and morphology of PLA-PLH nanoparticles. Using the anti-tumor drug 2-methoxyestradiol (2-ME) as a model drug, the drug delivery system PLA-PLH/2-ME was prepared by the solvent exchange method, and the drug loading and encapsulation efficiency were detected. At the cellular level, the inhibitory effects of the PLA-PLH/2-ME drug delivery system on CT26 colon cancer cells proliferation and migration were investigated. Finally, a fluorescent dye 1,1'-octacosyl-3,3,3',3'-tetramethylindocyanine iodide (DIR) was used the fluorescent marker, and the distribution of PLA-PLH/DIR in vivo was investigated. Results showed that PLA-PLH nanoparticles were successfully constructed, with an average particle diameter of (224.93 ± 13.05) nm. When the mass ratio of PLA-PLH to 2-ME was 1∶0.6, the drug loading and encapsulation efficiency were (27.86 ± 0.19)% and (64.38 ± 0.50)%, respectively. In cellular experiments, PLA-PLH could significantly enhance the uptake of the drug system by CT26 cells. Compared with free 2-ME treated group, both the inhibition rate of cell proliferation and the cell migration of CT26 cells treated with PLA-PLH/2-ME were significantly increased. In vivo imaging of mice and ex vivo imaging of various major tissues studies showed that PLA-PLH nanoparticles could reduce the degradation of DIR in the gastrointestinal tract and enhance the accumulation of DIR in colon region after oral administration.
Gelation Systems and Mechanisms of Chondroitin Sulfate-based Injectable Hydrogels
WANG Qin, QIU Yuzhi, QIAO Weihua, DONG Nianguo, YANG Yajiang
 doi: 10.14133/j.cnki.1008-9357.20200811001
[Abstract](42) [FullText HTML](29) [PDF 1334KB](9)
Chondroitin sulfate (ChS) is the sulfated glycosaminoglycan, a kind of natural polysaccharide, which is widely distributed in the extracellular matrix and on the surface of animal cells. ChS possesses various biological activities, such as promoting cartilage growth, regulating growth factors and accelerating wound healing, etc. As a novel biomaterial, in recent years, ChS-based injectable hydrogels have attracted much attention due to their biocompatibility, biodegradability combined with their unique bioactivity, particularly, their applications in the fields of tissue engineering, drug delivery, cell therapy and so on. The gelation systems, gelation mechanisms and modification methods of ChS-based injectable hydrogels are reviewed in this paper. Herein, the formation methods of the three dimensional network structure in ChS-based injectable hydrogels are mainly introduced, involving physical thermo-induced gelation, chemical crosslinking through Schiff’s base formation, click chemical reaction, formation of amide bonds and photo-crosslinking, etc., and enzyme-catalyzed crosslinking. These developed precursor polymer systems, the corresponding crosslinking methods and mechanisms have been illustrated in detail. In addition, the methods about regulating gelation time, mechanical properties and tissue adhesion are also discussed in this paper. The reported strategies can be reduced to the combination of two or more crosslinking methods, adjusting the constitute of the gelation systems and forming composite hydrogel, etc. Finally, future development of ChS-based injectable hydrogels as biomaterials is prospected. We propose more feasible injectable hydrogel systems with suitable properties will be developed. And the relationships among the chemical structure of ChS, the gelation behavior and biological functions should be studied further. In addition, benefiting the excellent bioactivity of ChS, ChS-based injectable hydrogels applied in other biomedical fields may be explored.
Research Advance in Polymer Stabilized Liquid Crystals
ZHANG Yang, YANG Weiping, ZHAO Wei, LI Ming, ZHOU Guofu
 doi: 10.14133/j.cnki.1008-9357.2020.0713001
[Abstract](33) [FullText HTML](29) [PDF 2020KB](6)
Polymer-stabilized liquid crystals (PSLCs) present excellent performance in the applications such as display, sensing, temperature control, and smart materials. It has attracted lots of interest in the research field of liquid crystal (LC) materials. This review introduces the PSLC materials with different phases, including nematic, cholesteric, ferroelectric, blue phase, and other LC phases. The characteristics and optical performances of PSLCs are described in detail, with the function of polymer networks in different PSLCs specially emphasized and explained. The research progress of in the field is reviewed, and the opportunities and challenges faced by PSLC materials are pointed out, aiming to promote the development and utilization of polymeric functional materials.
Magnetic Chitosan-Supported Polyoxometalates and Its Catalytic Oxidation of Tetrahydrothiophene
LIU Yefeng, LYU Ying, LI Ruiqi, ZUO Peng, WANG Ruixin
 doi: 10.14133/j.cnki.1008-9357.20200228001
[Abstract](960) [FullText HTML](361) [PDF 1450KB](4)
Firstly, Fe3O4 nanospheres were prepared by solvothermal method, which were used as magnetic cores and coated with chitosan (CS) crosslinked by glutaraldehyde. Then, polyoxometalate (POM) was supported onto the magnetic CS 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.
CO2 Adsorption and Catalytic Performance of Porphyrin-Based Porous Organic Polymers
LIU Cheng, LI Guoning, ZHANG Manxia, WENG Zhihuan, JIAN Xigao
 doi: 10.14133/j.cnki.1008-9357.20200116001
[Abstract](1105) [FullText HTML](442) [PDF 1102KB](12)
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, 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.
Co-Bonded Combretastatin Vascular Disrupting Agents and BLZ945 Polymeric Nanodrug for Synergistic Cancer Therapy
WANG Yue, SHEN Na, WEI Qi, TANG Zhaohui
 doi: 10.14133/j.cnki.1008-9357.20200612001
[Abstract](584) [FullText HTML](262) [PDF 1318KB](26)
Vascular disrupting agents (VDAs) have aroused increasing interest due to their great potential in cancer therapy. As compared to combretastatin A4 phosphate (CA4P), a polymeric VDA prodrug which has been in Phase III clinical trials, poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/combretastatin A4 (C-NPs), can significantly improve the tumor blood vessels targeting and enhance therapeutic effect due to the low permeability of nanodrug in solid tumors. However, C-NPs was found to induce the polarization of TAMs toward an M2-like phenotype (M2-TAMs) and further tumor recurrence, thereby limiting its antitumor application. BLZ945 was a highly selective CSF-1R inhibitor which can decrease the number of M2-TAMs through inhibiting CSF-1/CSF-1R signal pathway. However, CSF-1R is widely expressed in most cells of mononuclear phagocytic system, resulting in the lack of tumor selectivity and therapeutic side effect of BLZ945. Firstly, the reduction of M2-TAMs after BLZ945 treatment was verified by flow cytometry analysis; and in vivo antitumor efficacy showed that the combination of C-NPs and BLZ945 remarkably enhanced anticancer efficacy with a tumor suppression rate of 74.1%. Then, the co-bonded nanodrug poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)-combretastatin A4/BLZ945 (CB-NPs) was developed for further enhance the synergistic anticancer efficacy. The chemical structure of CB-NPs was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). The obtained CB-NPs had a hydrodynamic radius of (56 ± 19) nm in aqueous solution determined by dynamic light scattering (DLS). The drug loading content of CA4 and BLZ945 in CB-NPs measured by HPLC was 10.7 and 8.4%, respectively. An in vivo study with the C26 murine colon carcinoma model showed that CB-NPs exhibited the most prominent suppression of tumor growth, significantly higher than the combination therapy with C-NPs plus BLZ945. The tumor suppression rate to C26 tumor with an initial volume of 410 mm3 was 79%. Therefore, CB-NPs enhanced tumor targeting ability of BLZ945 and improved its synergistic antitumor ability. This work provides a valuable cooperative strategy therapeutic choice of VDAs for solid tumor therapy.
Design and Preparation of Polystyrene-based Porous Polymers with Triazine Crosslinker
QIU Yuqian, LIU Qianhui, HAN Haojie, YU Tao, WANG Hongqiang, XU Fei
 doi: 10.14133/j.cnki.1008-9357.20200520001
[Abstract](85) [FullText HTML](55) [PDF 1512KB](3)
Hypercrosslinked porous polymers (HCPs) possess structural advantages of high specific surface areas, adjustable functionalities, controllable pore structures and low cost. Therefore, they have widespread application prospect in many fields, such as gas storage, adsorption/separation, drug release and catalysis. Development of crosslinked structure is of importance to construct novel HCPs with optimized porous structures and new properties in emerging fields. Herein, a series of triazine-crosslinked HCPs from polystyrene were fabricated through Friedel-crafts hypercrosslinking reaction, in which cyanuric chloride was introduced as crosslinking agent. Using linear polystyrene and polystyrene spheres as raw materials, HCPs with three-dimensional network nanostructure and spherical morphology were obtained, respectively. Field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, N2 adsorption-desorption tests were performed to investigate the microstructure, chemical structure, and pore structure. The results show that the triazine crosslinking structure provides much higher surface area and richer mesopores below 10 nm in the asobtained HCPs, compared with previously reported carbonyl crosslinking structures. The hypercrosslinking conditions of raw material concentration and crosslinking time were further investigated. The results show that lower polystyrene concentration gives rise to higher surface area in the resulting three-dimensional network HCPs because of developed mesopores; while increase of hypercrosslinking time results in enhanced microporous surface area and the rising tendency levels off after 2 h. Furthermore, the proposed triazine crosslinking strategy can be implemented using commercial polystyrene, leading to similar triazine-crosslinked HCPs with three-dimensional network structure. Therefore, our finding opens up a new avenue for waste-to-wealth recycle of polystyrene, which is one source for causing so-called “white pollution”.
Surfactant-Assisted Interfacial Synthesis of Crystalline, Two-Dimensional Polymers
ZHUANG Xiaodong
[Abstract](97) [FullText HTML](57) [PDF 622KB](53)
Organic two-dimensional (2D) materials have become one of the emerging topics, due to their potential unique physical and chemical properties. The preparation of 2D polymers with large area, controllable thickness and long-range ordering features remains challenge. Many new organic 2D materials have been reported in the past few years. However, many organic 2D materials possess obvious disadvantages, including poor crystallinity, limited ordering size. Recently, Xinliang Feng's group at Dresden University of Technology reported the controllable preparation of crystalline two-dimensional polymer by surfactant-monolayer-assisted interfacial synthesis, (denoted SMAIS). The key of this method is the surfactant monolayers at the gas-liquid interface can limit molecules or precursors to the 2D interface, for further polymerization. The regulation of the repeating structure and crystallinity of as-prepared 2D polyaniline (2DPANI), 2D polyimide (2DPI) and 2D polyamide (2DPA) were very well studied. This method provides a new strategy for preparation of crystalline organic 2D polymers.
Self-healing Electrolyte Material Based on Quadruple Hydrogen Bond
LIANG Zijia, LI Yu, FENG Wei
 doi: 10.14133/j.cnki.1008-9357.20200608002
[Abstract](613) [FullText HTML](340) [PDF 1176KB](11)
As a lightweight energy system, lithium ion batteries are used in different industries and fields. The electrolyte acts as a channel for ion transmission in the battery. Polymer materials are applied as electrolyte since they have the advantages of high safety, high thermal stability and high mechanical strength. However, polymer will crack in certain external environments. Thus some researchers proposed to prepare self-healing materials and applied them to electrolyte in lithium ion battery. This work was dedicated to solve the problem that the polymer electrolyte is susceptible to mechanical damage. The preparation method of 2-ureido-4-[1H]-pyrimidinone (Upy) unit which contains the quadruple hydrogen bonds was raised. And grafted Upy on the Polyvinyl alcohol (PVA) polymer matrix was performed to prepare a self-healing electrolyte material. The chemical structure, the thermal stability, the self-healing ability and electrochemical performance of PVA-Upy membrane were studied. The results showed that PVA-Upy material was successfully prepared by this method and proved by FT-IR and 1H-NMR measurement. PVA-Upy material showed good thermal stability and mechanical strength, and had a self-healing efficiency of 90.20% in tensile strength at 70 ℃. As for electrolyte, it had an electrochemical window of 5 V and its highest ion conductivity was 2.06×10−3 S cm−1. Assembling it as LiFePO4/PVA-Upy/Li cell, it showed good cycle stability, suggesting its application prospect in lithium ion batteries.
Synthesis and Properties of Cottonseed Oil-Based Polyurethane Elastomer
LI Jia, XU Zhimei, XI Zhenhao, ZHAO Ling
 doi: 10.14133/j.cnki.1008-9357.20200301001
[Abstract](658) [FullText HTML](352) [PDF 1229KB](9)
Bio-based polyurethane with good comprehensive performance has attracted increasing attention. Cottonseed oil-based polyurethane (TO-PU) elastomers were synthesized from ozonized cottonseed oil-based polyols (OTO-polyols) with high hydroxyl value and castor oil (CO) by reacting with isophorone diisocyanate (IPDI). The structure of urethane bond was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the formation of hydrogen bond was observed. The thermo-mechanical properties of synthetic TO-PU were examined by differential scanning calorimeter , thermogravimetric analyzer and universal testing. The thermo-mechanical properties are strongly dependent on the crosslinking density of TO-PU. The glass transition temperatures of polyurethane elastomers are −35 — −28 ℃, and the crystalline properties can be enhanced with the increase of castor oil. Correspondingly, the mechanical properties of TO-PU according to the tensile behavior of elastomers can be adjusted by turning the mass ratio of OTO-polyols to CO. The tensile strength of TO-PU-3 (m(OTO-polyols):m(CO)=7:3) exceeded 2.50 MPa, while the elongation at break can maintain above 150%. In comparison, the elongation at break of TO-PU-1 (m(OTO-polyols):m(CO)=9:1) can approach 400% by reducing the content of castor oil. The cottonseed oil-based polyurethane elastomer shows excellent thermal stability with the initial decomposition temperature above 240 ℃, and its three thermal degradation stages are caused by urethane groups, ester groups, and long carbon chains of polyols, respectively.
Low-Temperature Self-Healing Polymer Based on Hydrogen Bonding Crosslinking
GAO Long, YU Huitao, WANG Jian, FENG Yiyu, FENG Wei
 doi: 10.14133/j.cnki.1008-9357.20200608001
[Abstract](658) [FullText HTML](355) [PDF 1067KB](12)
In some extreme environments, polymers are easy to suffer from irreversible damage or degradation, which increases potential safety problems and reduces the service life of the materials. Regarding to the problem of low self-healing rate of the polymer at low temperature, the polymer network with cross-linked multiple hydrogen bonds was prepared by mixing up the polydimethylsiloxanes with amino-terminated flexible molecular chains and malonyl chloride, which were subjected to condensation polymerization at the temperature of −5 ℃ and in Ar atmosphere. The flexible molecular chain effectively reduces the glass transition temperature (Tg≈−120 ℃), indicating that the molecular chain's ability to move still exists under the low temperature conditions, and it is a prerequisite for polymers to self-heal under low temperature conditions. The results showed that the self-healing efficiency of the tensile strength of the polydimethylsiloxane cross-linked polymer at −25 ℃ after 40 min was as high as 97%. Through the reversible fracture and formation of multiple hydrogen bonds between N—H and C=O, the rapid self-healing of polymers at room temperature and high-efficiency self-healing at low temperature can be achieved. This study will provide an insight for further preparation of the autonomous self-healing materials under the extreme environments in the future.
Cooperative Self-Assembly of Polypeptide Homopolymer/Block Copolymer into Helical Nanotoroids
MA Chen, HUANG Xiaoyu
 doi: 10.14133/j.cnki.1008-9357.20200804001
[Abstract](102) [FullText HTML](84) [PDF 483KB](3)
Toroids have attracted widespread attention due to their unique structures and properties. Chiral structures are ubiquitous in nature and chiral materials display excellent performance in diverse fields. Polymer self-assembly is an efficient way toward various nanostructures including nanotoroids and chiral nanostructures. However, currently, there is no report regarding chiral toroidal nanostructures by self-assembly of polymers. Recently, the group of Prof. Lin Jiaping and Prof. Cai Chunhua from East China University of Science and Technology has reported that a binary system containing polypeptide homopolymer and its block copolymer can self-assemble into uniform chiral nanotoroids in solution. In such a unique structure, the homopolymers aggregate into fibrils and then convolve into a toroidal template, resembling the toroidal condensation of DNA. While the block copolymers self-assemble on the homopolymer toroids forming helical surface nanopatterns, the chirality and width of the surface helical patterns can be varied by the chirality and molecular weight of the polypeptide block copolymers. Their work not only proposes a novel route toward uniform nanotoroids, but also provides a new strategy constructing chiral nanopatterns on the surface of toroids.
Hyaluronan-Based Functional Materials For Their Biomedical Applications
ZHU Yirui, CAI Zhixiang, GUO Yalong, ZHANG Hongbin
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20200615001
[Abstract](131) [FullText HTML](60) [PDF 1953KB](31)
Hyaluronan (hyaluronic acid, HA HA) is a linear polysaccharide with disaccharide repeats of D-glucuronic acid and N-acetyl-D-glucosamine. As one of the most important glycosaminoglycans, HA is widely distributed in the human body including the extracellular matrix of the vitreous of the eye and cartilage tissue. The physiological functions of HA in the human body to maintain moisture, regulate osmotic pressure, lubricate joints and absorb shock are closely related to their physicochemical properties and rheological properties. The applications of HA-based functional materials mainly include the following three aspects: (1) various HA-based derivatives and hydrogels are prepared based on the chemical modifications of hydroxyl, carboxyl, and acetamido groups. (2) HA and its derivatives have been widely used as drug carriers for targeted drug delivery based on HA interacting with receptors on the surface of cancer cells (such as CD44, RHAMM and LYVE-1 receptors, etc.), and (3) HA hydrogels have been widely used in tissue engineering based on the close relationship between HA and human physiological activities. The HA-based biomaterials and their applications in the biomedical filed (such as cancer targeted therapy, wound healing, postoperative adhesion, cartilage regeneration, Osteoarthritis treatment, etc.) have been summarized in this review.
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Towards Commercial Photovoltaic Materials: A New Class of Polymeric Donor Materials with Low Cost and High Efficiency
2020, 33(5): 415-420.   doi: 10.14133/j.cnki.1008-9357.20200618001
[Abstract](780) [FullText HTML](371) [PDF 689KB](20)
High efficiency, high stability and low cost are the three key factors for polymer solar cell (PSC) that determine whether this technology could be commercialized. In recent years, the power conversion efficiency of PSC has reached a high level over 17%. However, the high efficiency devices are realized mainly based on photovoltaic donor and acceptor materials with complex structures and high cost, so it becomes a major challenge to reduce the cost of photovoltaic materials for the commercialization of PSC. Since 2018, a research group of Professor Li Yongfang from the Institute of Chemistry, Chinese Academy of Sciences have reported a series of photovoltaic polymer donors based on poly(thiophene-quinoxaline) derivatives, showing high efficiency, high stability and low cost for potential commercial application. Based on the synthesis of new polymers, they also discussed the effect of fluorination and methylation on the energy level and photovoltaic performance of new polymer donors. The works provide a new concept for the design of polymer donors with potential for commercial application.
Invited Reviews
Recent Advances on Macromolecular Nanovectors for Carbon Monoxide Delivery
ZHANG Mingyang, CHENG Jian, HU Jinming
2020, 33(5): 421-432.   doi: 10.14133/j.cnki.1008-9357.20200327001
[Abstract](1244) [FullText HTML](538) [PDF 1586KB](38)
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 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 time and optimizes the biodistributions. In this review, we summarize the recent achievements of CO-releasing macromolecules and highlight three approaches used for the fabrication of CO-releasing macromolecules. 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.
A Stretchable and Rapidly Self-Healable Polysiloxane Elastomer Based on Reversible Ionic Hydrogen Bonds
SHI Jinfeng, ZHAO Na, FU Wenxin, LI Zhibo
2020, 33(5): 433-440.   doi: 10.14133/j.cnki.1008-9357.20200228002
[Abstract](1277) [FullText HTML](494) [PDF 981KB](14)
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 PDMS (PDMS-g-COOH and PDMS-g-NH2) was 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 at break with a stretching speed of 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 being restored at room temperature for 30 min.
Synthesis and Nonlinear Optical Performance of Triphenylamine-Fluorene Copolymer Covalently Bridged [60]Fullerene Triad
2020, 33(5): 441-451.   doi: 10.14133/j.cnki.1008-9357.20200111001
[Abstract](2308) [FullText HTML](430) [PDF 1494KB](10)
As one of the quasi-zero-dimensional materials, [60]fullerene (C60) and its organic/polymeric derivatives exhibit great application potential 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 PTF terminated with two aldehyde groups (CHO-PTF-CHO). This material, 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 were investigated through an open-aperture Z-scan setup at 532 nm.The C60-PTF-C60/PMMA film exhibited more excellent NLO and OL responses when compared to the 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 OL threshold were 437.75 cm/GW, 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.
Preparation and Solution Properties of Tadpole-Shaped Double Hydrophilic Diblock Copolymers
ZHANG Long, ZHANG Guoying
2020, 33(5): 452-459.   doi: 10.14133/j.cnki.1008-9357.20191008001
[Abstract](4393) [FullText HTML](945) [PDF 1198KB](28)
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-lPNIPAM-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 of aggregates size with the increasing solution temperature.
Multi-Responsive Phase Inversion of Emulsions Stabilized by Responsive Block Copolymers
HUANG Limin, PENG Wenli, HAN Xia, LIU Honglai
2020, 33(5): 460-466.   doi: 10.14133/j.cnki.1008-9357.20191202002
[Abstract](2557) [FullText HTML](533) [PDF 1045KB](16)
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 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 fraction of water volume (φw) was less than 0.7, the emulsion was W/O type. However, when φw≥0.7, a catastrophic phase inversion occurred where the system shifted in the opposite direction and O/W type emulsion was obtained. These results will have potential applications in the field of controlling drug release.
Effect of Metal Ion Loading on Thermal Decomposition Temperature of Surface Modified Polyimide Films
ZHAN Linzhong, WU Lijia, TIAN Guizhi, WU Haisheng, TIAN Guofeng, QI Shengli, WU Dezhen
2020, 33(5): 467-472.   doi: 10.14133/j.cnki.1008-9357.20191119001
[Abstract](4602) [FullText HTML](929) [PDF 1002KB](15)
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 (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 by 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 (TG) analyzer under a nitrogen atmosphere was performed to investigate the effect of different metal ions on the thermal decomposition temperature of PI film. It was found that the strong alkali metal ions, K+ and Na+, provided obvious degradation effects on the PI film, which caused a significant decrease in the thermal decomposition temperature of the PI film. 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 film. The effect of metal ions on the thermal decomposition temperature of the film was positively correlated with the alkalinity(pKb) of its corresponding hydioxide, ie K+> Na+ >> Ca2+ ≈ Mg2+ > Ag+ ≈ Al3+.
Preparation and Properties of Novel Sulfonated Poly(ether ketone benzimidazole) Copolymers for Fuel Cells
GUO Yufei, GUO Zhihai, ZHANG Chongyin, WANG Wenbin, LIU Feiyue, GUO Xiaoxia, FANG Jianhua
2020, 33(5): 473-482.   doi: 10.14133/j.cnki.1008-9357.20191230001
[Abstract](2178) [FullText HTML](488) [PDF 1146KB](7)
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 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 the 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 test of H2-O2 single cell 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 assembled with Nafion212 (631 mW/cm2) under the same test conditions.
Effects of Lysine-Grafted Graphene Oxide on the Mechanical and Osteogenesis Properties of Shape Memory Capable PLCL Fibers
LIU Chang, YI Bingcheng, WANG Xianliu, SHEN Yanbing, QIN Chunping, ZHANG Yanzhong
2020, 33(5): 483-491.   doi: 10.14133/j.cnki.1008-9357.20191208001
[Abstract](2219) [FullText HTML](470) [PDF 1056KB](29)
Graphene oxide (GO) nanosheets with varied mass fractions 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 nanofiber films, an optimal GO mass fraction(m(GO)∶m(PLCL)), 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 1-(3-dimethy laminopropyl)-3-ethylcarbodiimide/N-hydroxysuccinimide chemistry followed by electrospinning for the generation of multifunctional Lys-GO/PLCL nanofibers. A series of characterization including mechanical properties, shape memory performance, acidity neutralization capacity and osteogenic differentiation 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, which was evidenced by 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 that 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 neutralize the acidic degradation products of the PLCL (e.g., the pH acidity was neutralized to 5.2 for the Lys-GO/PLCL 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 mouse bone mesenchymal stem cells (rBMSCs). This newly developed shape memory capable Lys-GO/PLCL fibers may find applications in the construction of multifunctional bone tissue engineering scaffolds.
Degradation Performance of Typical Biodegradable Polyesters in Seawater
WANG Gexia, HUANG Dan, ZHANG Wei, JI Junhui
2020, 33(5): 492-499.   doi: 10.14133/j.cnki.1008-9357.20191015001
[Abstract](3566) [FullText HTML](891) [PDF 773KB](43)
With the increasing pollution of marine plastic, the degradation properties of biodegradable plastic in seawater have attracted much attention and controversy. Four typical biodegradable polyesters polylactide (PLA), poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS) and poly(ε-caprolactone) (PCL), were selected. The degradability of these materials in seawater was studied by investigation of the change of their mass loss, molecular weight, mechanical properties, and spline morphology after being immersed in natural seawater for 364 d. 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 degradation is the fastest and the mass loss of PCL degradation is 32%. Microorganisms seem to be the key factors affecting the rate of biodegradation. It is also found that the high concentration of inorganic salt has a promotion to the non-enzymatic hydrolysis process.
Preparation of Raspberry-Like PDA-Cu NPs Nanoparticles with Antibacterial Properties
ZHU Jiaying, LI Ting, DING Zhongyang, DONG Weifu
2020, 33(5): 500-506.   doi: 10.14133/j.cnki.1008-9357.20200103001
[Abstract](1409) [FullText HTML](549) [PDF 1212KB](13)
In this paper, raspberry-like polydopamine/copper nanoparticles (PDA-Cu NPs) were constructed by simply adjusting the contents of copper source and reduction temperature on the basis of good adhesion properties of polydopamine (PDA) with metal particles. The successful introduction of copper nanoparticles was confirmed by measurements of X-ray diffraction (XRD) and Zeta potential. Scanning electron microscopy (SEM) results showed that the raspberry-like structure had been successfully constructed. When the reduction temperature was 60 ℃, the copper nanoparticles had more uniform particle size. When the mass ratio of PDA to copper nitrate was more than 1/6, 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 had good antibacterial properties. The antibacterial activity of raspberry-like nanoparticles was 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 could be achieved, and its antibacterial performance against S.epidermidis was better than that of E.coli. The bacterial zone experiments showed that PDA-Cu NPs (1/6, mass ratio of PDA to copper nitrate) had a clear zone of inhibition and its diameter was larger than that of PDA-Cu NPs (1/8), suggesting the optimal antibacterial properties. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of raspberry-like nanoparticles made from optimal reaction conditions for E.coli were 48.7 μg/mL and 195.0 μg/mL, respectively, while the MIC and MBC values for S.epidermidis were 39.0 μg/mL and 97.5 μg/mL, respectively. Raspberry-like nanoparticles showed good abtibacterial properties, which were expected to have a good application in biomedical fields.
Fabrication of Hyaluronic Acid-Based Micropatterning and Investigation of Its Biocompatibility
CHANG Lingxue, HE Hongyan, JIN Lili, LIU Changsheng
2020, 33(5): 507-514.   doi: 10.14133/j.cnki.1008-9357.20190713001
[Abstract](978) [FullText HTML](419) [PDF 1662KB](10)
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 cross-linked with N′-(ethyliminomethylidene)-N, N-dimethyl-1,3-propylene diamine (EDCI) and adipic acid dihydrazide (ADH). Then, the HA microwell patterns were fabricated by soft-lithography technique. By turning the mass fraction of ADH and EDCI from 8.3% 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 mass fraction of ADH and EDCI increased, the crosslinking degree of the film increased, and the swelling variation of gel became smaller. HA films with high mass fraction of ADH and EDCI showed a slower degradation behavior. A series of HA films with micro-array pore structure (pore diameter of 32, 96, 128, 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 rat bone mesenchymal stem cells (rBMSCs) compared to the smooth HA gel film, while the small micron wells (32 μm) with compact distribution can significantly promote the proliferation and osteogenic activity of rBMSCs.