N-succinyl chitosan–dialdehyde starch hybrid hydrogels for biomedical applications

A new class of injectable, biocompatible and biodegradable hydrogel is reported. This hydrogel is derived from N-succinyl chitosan (SCS) mixed with water-soluble dialdehyde starch (DAS) without using a conventional chemical crosslinker. The hybrid hydrogel is formed owing to the Schiff’s base reaction between amine groups of SCS and dialdehyde groups of DAS to form —CH[bond, double bond]N— group. SCS, DAS, and SCS–DAS hybrid hydrogels were synthesized and then characterized by FTIR analysis spectroscopy. The influence of SCS:DAS ratio in hybrid polymers solution on physicochemical properties of resultant hydrogels (e.g. gelation time, gel fraction (%) and equilibrium swelling ratio), surface morphology, in vitro weight loss (%), and mechanical stability was examined. The results demonstrated that SCS content has a profound role for forming tighter crosslinked hybrid hydrogels, where the increase of SCS content reduces the time for hydrogel forming. Also, the water uptake and hydrolytic weight loss decrease. Meanwhile, the DAS content increases, and mechanical properties of SCS–DAS hybrid hydrogels decrease. Curcumin release profile and adhered HGF cells on hydrogel surface sharply influenced the SCS portion in hybrid hydrogel composition. The SCS–DAS hybrid hydrogel properties afforded a possible opportunity to be used as a covalent in situ forming hybrid hydrogels in biomedical applications such as, tissue engineering and cartilage repair.