Three kinds of cross-linked chitosan films were prepared with hexamethylene diisocyanate (HDI), epichlorohydrin (ECH) and glutaraldehyde (GA) as cross-linking agents, respectively. The physical and mechanical properties, biodegradability and Schwann cell affinity of the cross-linked films were investigated. A significant decrease in the degradation rate in lysozyme solution and a large change in the mechanical properties were observed compared with non-cross-linked chitosan films. The protein adsorption on chitosan films was determined by means of enzyme-linked immunosorbent assay (ELISA). In comparison with the non-cross-linked films, the chitosan films cross-linked with HDI showed a significant increase (up to 40-50%) in both fibronectin and laminin adsorption, while the protein adsorption on the other two kinds of cross-linked films was similar to that on non-crosslinked films. In addition, cell culture revealed that the HDI cross-linked chitosan films enhanced the spread and proliferation of Schwann cells while the other cross-linked films delayed the cell proliferation. These results suggest that HDI cross-linking of chitosan films provides a combination of physical properties, biodegradability and Schwann cell affinity suitable for peripheral nerve regeneration.

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Starch has been widely explored in food additives such as thickeners, stabilizers, and gelling agents due to its excellent properties. However, the poor dispersion and emulsification of starch limit direct applications. To overcome this challenge, starch is extracted from potatoes and etherified to carboxymethyl starch sodium (CMS) to form a cold water soluble starch, which is prepared as an amphiphilic colloid by esterification with lauric acid using Novozym 435 catalyst. As a result of the new groups introduced and concomitant changes produced in the granule structure, carboxymethyl starch sodium laurate starch (CMS‐LS) typically shows strong emulsifying properties, low surface tension, and good amphiphilic properties. Characterizations by Fourier transform infrared (FTIR), Scanning Electron microscope (SEM), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS) show that CMS‐LS is successfully prepared. The results of water solubility, surface tension, contact angle measurement, and emulsification test indicate that CMS‐LS is an excellent emulsifier, amphiphilic polymer and surfactant. Therefore, CMS‐LS is successfully synthesized and esterified, which can be widely used in food, cosmetics, and biomedicine fields.