Preparation and antibacterial properties of curcumin-loaded cyclodextrin-grafted chitosan hydrogel

The chitosan hydrogel has been widely appraised for drug delivery systems. However, its long gel formation time, poor drug release effect, and low drug loading capacity for hydrophobic drugs limited its wide application. Herein, the β-cyclodextrin-grafted chitosan (CD-g-CS) with different degrees of substitution (DS) was successfully synthesized from O-p-toluenesulfonyl-β-cyclodextrin (Ts-CD) and chitosan (CS). The novel thermosensitive β-cyclodextrin-grafted chitosan/glycerophosphate (CD-g-CS/GP) hydrogels were prepared in the presence of αβ-glycerophosphate (GP). The CD-g-CS/GP hydrogels had a gel time of less than 6 min and performed great injection performance. In vitro release studies revealed that the hydrogels not only had a sustained release but also enhanced the solubility and bioavailability of curcumin (CUR). And the CD-g-CS/GP hydrogel had suitable swelling behavior, porosity, and degradation rate. In addition, the hydrogels exhibited good hemocompatibility. The evaluation of the antibacterial activity indicated that CUR@CD-g-CS/GP hydrogels were effective antibacterial materials for Staphylococcus aureus and Escherichia coli . In summary, the results suggested that the CD-g-CS/GP hydrogel might be used as a potential biodegradable smart drug-sustained release system for the controlled release of hydrophobic drugs, which has broad application prospects in the field of biomedicine. Graphical Abstract Preparation of CUR@CD-g-CS/GP hydrogel. First, the prepared CD-g-CS was dissolved in 0.1 M HAc solution. The GP powder was dissolved in distilled water to prepare a GP solution of 50% (w/v). Next, the GP solution was added dropwise to the CD-g-CS solution and stirred in an ice bath. Finally, the CD-g-CS/GP hydrogel was obtained. The hydrogel-loaded CUR (CUR@CD-g-CS/GP) was prepared by adding CUR to the CD-g-CS solution. After incubation at 37 °C, the system changed from a sol to a gel state. The gel was placed in a release medium and the drug molecules were released from the system.