The influence of molecular weight of chitosan on physical and biological properties of collagen/chitosan scaffolds

Abstract

Biopolymer blends between collagen and chitosan have good potential for production of biocompatible scaffolds. However, the relationship between the molecular weight of chitosan and its effect on physical and biological properties of collagen/chitosan scaffolds have not been clearly elucidated. This research aims to investigate the effects of molecular weight of chitosan on physical and biological properties of collagen/chitosan scaffolds. Porous scaffolds were fabricated by freeze drying solutions of collagen, chitosan, and collagen/chitosan blends and then crosslinked by dehydrothermal treatment (DHT). Various scaffolds were prepared using four chitosan samples with various molecular weights (Mv, 4.8k-880k) and blending compositions. Fourier transform infrared (FT-IR) spectroscopy proved that collagen/chitosan scaffolds in all blending compositions contained only physical but not chemical interaction in molecular level. The compressive modulus of scaffolds decreased with increasing the compositions of chitosan, but, for collagen blended with high molecular weight chitosan (880k), the compressive modulus increased, especially at blending composition of 30% chitosan. Equilibrium swelling ratios of approximately 6-8, carried out in phosphate buffered saline at physiological pH (7.4), were found in case of collagen dominate scaffolds. The lysozyme biodegradation test demonstrated that the presence of chitosan, especially the high molecular weight, could significantly prolong the biodegradation of collagen/chitosan scaffolds. In vitro culture of L929 mouse connective tissue fibroblasts and Detroit 551 human dermal fibroblasts evidenced that collagen scaffold with lower molecular weight chitosan was more effective to promote and accelerate cell proliferation than pure collagen and collagen/high molecular weight chitosan scaffolds, particularly for scaffolds containing 30% of chitosan. The results elucidated that the blends of collagen with low molecular weight chitosan have a high possibility to be applied as new materials for skin tissue engineering.