Cyclodextrin grafted chitosan thermosensitive hydrogel using dual gelling agents: Drug delivery and antibacterial materials

In this paper, three kinds of cyclodextrin-grafted-chitosan (CD-g-CS) were synthesized from chitosan (CS) and beta-cyclodextrin (beta-CD) with different ratios. And a series of hydrogel with good temperature sensitivity and injectability were prepared by using sodium glycerophosphate (GP) and ammonium hydrogen phosphate (AHP) as dual gelling agents. The gelation formation time of hydrogel was short, and the shortest time was 0.75 min. The FTIR spectrum and 1H-NMR spectrum showed the structure of the compounds and intermolecular interactions. The molecular docking technique probed the encapsulation mechanism of the drug with beta-CD. The SEM results showed that the hydrogel had a highly interconnected three-dimensional spatial structure. The swelling ratio of hydrogel was not less than 150 % within 1 h and the degradation rate of hydrogel was not less than 75 % within 14 days. The in vitro drug release results showed that the hydrogel had optimal sustained release effect, and the cumulative release ratio was 58.3 % in 34 h. The release kinetics analysis exhibited that the hydrogel conformed to the Riter-Peppas model. The hemocompatibility test and cytotoxicity test proved that the hydrogel had good biocompatibility and biosafety. The antibacterial experiments showed that the hydrogel could inhibit the biological activity of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Therefore, the CD-g-CS/GP-AHP hydrogel has a broad application prospect in the biological fields of drug delivery and antibacterial materials.