Fabrication and characterization of chitosan-based composite scaffolds for neural tissue engineering

With the development of peripheral nerve tissue engineering, study of biodegradable materials have extensive applied prospect. Chitosan (Cs) is a promising candidate for neural tissue engineering due to its similar chemical structure to glycosaminoglycan. However, due to its lack of elasticity and flexibility, Cs often needs to be used in combination with other materials. In this study, three composite scaffolds were prepared by freeze-drying method: Cs/hyaluronic acid (HA)/gelatin (Gel), Cs/collagen (Col), and Cs/polyethylene glycol (PEG). Mechanical properties, swelling behavior, porosity, and conductivity of these materials have been characterized. Compared with pure Cs, the addition of other materials reduced the average pore size, while improved the mechanical properties of the composite scaffold. Furthermore, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), live/dead staining, cell morphology, and immunofluorescence staining were performed to evaluate the cytotoxicity, biocompatibility, and differentiation of rat pheochromocytoma (PC12) cells on Cs/HA/Gel, Cs/Col, and Cs/PEG composite scaffolds. Our results indicated that all these Cs-based composite scaffolds had good biocompatibility without cytotoxicity, while Cs/PEG scaffolds possessed higher cell survival rate and could promote the adhesion, proliferation, and differentiation of PC12 cells. The Cs-based composite scaffolds developed in this study can serve as promising substitutes for neural tissue regeneration.