Tailoring of chitosan scaffolds with heparin and γ-aminopropyltriethoxysilane for promoting peripheral nerve regeneration

Chitosan has been well known for promoting peripheral nerve regeneration, however, its effect is still not as good as that of autografts. In this study, the feasibility of using negatively charged heparin and positively charged γ-aminopropyltriethoxysilane (APTE) treatment as biocompatible modification of lyophilized porous chitosanscaffolds was evaluated. The morphology of the prepared chitosan scaffolds as a function of treatment with different charged molecules showed no significant differences, while a skin-like surface was observed for the scaffolds modified with high APTE concentration and heparin. The quantitative and qualitative characterization of heparin and amino densities by Toluidine Blue O (TBO) and Acid Orange (AO) assays confirmed the successful immobilization of heparin and APTE on the chitosan scaffolds. The measurement of surface charge densities indicated that the scaffolds treated with APTE showed increased charge densities while heparin decreased the cationic charge density. Moreover, the fabricated charge processed chitosan scaffolds were stable after immersion in phosphate buffer saline for more than ten days. Further on, the chitosan scaffolds processed with 2 mg/mL heparin did facilitate the attachment, proliferation and maintain the biological function of Schwann cells in vitro . The study demonstrates that chitosan scaffolds treated with suitable heparin concentration provides an effective selection for biomaterials surface modification and shows great potential for the application in peripheral nerve regeneration.