Preparation of Chitosan Scaffolds with Various Molecular Weights and Their Enzymatic Degradation In Vitro

Chitosan scaffolds serve as promising biomaterials in tissue engineering, especially as nerve graft materials. The ideal nerve grafts should be degraded in sync with nerve regeneration. In this study, chitosan scaffolds with different molecular weights were successfully prepared by heterogeneous H2O2 treatment. By prolonging the reaction time of chitosan (150 kDa) in H2O2 solution (1 wt%), the molecular weight of chitosan decreases gradually from 150 kDa to 45 kDa without altering the deacetylation. The porosity and swelling rate of the scaffolds with various molecular weights stayed constant but the scaffolds with larger molecular weight possess better mechanical strength. Significantly, the scaffolds with lower molecular weight were degraded faster in lysozyme solution. The in-vitro enzymatic degradation ratios of these scaffolds varied from 8.8% to 47.1% after 60 days, respectively. Meanwhile, there was no significant change in chemical structure of the residual scaffolds during enzymatic degradation confirmed by IR spec. Our work provides theoretical basis for manufacturing chitosan scaffolds with controllable in-vivo degradation rates by only altering their molecular weights to meet the convalescence of diverse nerve injury.