Construction of Chitosan with Oriented Porous Structure for Drug Carrier

Chitosan(CS) scaffolds(CS-RC) with radially gradient changes in pore size were prepared by modulating the ice crystal growth process, based on the role of temperature changes on polymer conformation. Results show that the temperature gradient difference in the outer edge region is larger than that in the inner core region at low temperatures, and thus, modulation of the ice crystal growth process can achieve a regular, controlled morphology distribution of the internal pore structure of the CS-RC scaffolds, with pore diameters ranging from 100 µm to 140 µm. The physicochemical performance evaluation results indicate that the CS-RC scaffolds possess good moisturizing properties and mechanical properties, stable degradation properties, and a high porosity of about 88.8%. Additionally, compared to traditional low-temperature lyophilized chitosan scaffold materials, the CS-RC scaffolds exhibit a significant increase in drug loading rates and encapsulation rates, increasing by 8.4% and 15.9% for the hydrophilic drug alendronate, and 4.8% and 11.5% for the hydrophobic drug rifampicin, respectively. The drugs also show a stable sustained-release process and an effective, sustained release cycle within the scaffolds.