Facile preparation of a strong chitosan-silk biocomposite film.

Chitosan-silk biocomposite films with nanofibrous structures have been prepared by facile solution casting of chitosan and silk co-dissolved in formic acid. The morphology, structure and mechanical properties of the chitosan-silk biocomposite were characterized by SEM, FTIR, TG-DSC, and mechanical testing. The results demonstrate that the prepared biocomposite films with a chitosan-silk ratio of 3:1 shows a high tensile strength of 97.8 MPa, a strain at break of 10.8% and a Young's modulus of 3.5 GPa, indicating its high strength and elasticity. Also, the preliminary cell culture experiment demonstrated the ideal biocompatibility of chitosan-silk composite films. As a result the superior mechanical properties of this composite film can be attributed to the silk nanofibrils and chitosan self-assembled nanofibers, and the strong hydrogen bonding interaction between the silk nanofibril and chitosan nanofibers. The specific nanostructure, enhanced mechanical properties, and biocompatibility make the biocomposite films a promising material for applications in biomedical devices.