Biocompatible and Biodegradable Bioplastics Constructed from Chitin via a Green Pathway for Bone Repair

Biodegradable plastics are urgently needed in the biomedical field to avoid the secondary surgery for implants after completing the repair of nonload bearing bone defects. Herein, novel chitin based plastics were successfully fabricated by changing the shape and aggregation state structure of chitin hydrogels through drying under a negative pressure, which led to a plastic deformation. The chitin hydrogels were prepared by using an environmentally friendly aqueous NaOH/urea solvent, and then radially oriented under the negative pressure to form chitin bioplastics (CP) on the basis of the removability of the chitin molecular bundles in the hydrogels. Moreover, hydroxyapatite (HAP) was in situ synthesized to obtain the chitin/HAP composite plastics (CHP). Their structure and properties were characterized by SEM, FTIR, C-13 NMR, X-ray diffraction and mechanical testing. The results indicated that the bioplastic preparation was a green physical process, and the incorporation of HAP reinforced significantly the tensile strength of CHP. The viability, biocompatibility, hemocompatibility and in vivo histocompatibility of the bioplastics were evaluated systematically. The introduction of HAP could improve the cell adhesion, proliferation and differentiation of the osteoblast cells. Moreover, CHP exhibited good histocompatibility, hemocompatibility and in vivo biodegradability, showing potential application in the bone tissue engineering field.