In vitro antibacterial activity and cytotoxicity of Thermo-sensitive composite hydrogels with encapsulated CuFe-LDH

Copper-iron layered double hydroxides (CuFe-LDHs) with varying Cu/Fe atomic ratios and intercalated CO32- / HCO3- anions were successfully synthesized via a solvothermal method. The as-prepared CuFe-LDHs exhibited a sheet-like morpHology, with particle size increasing as the Cu/Fe ratio increased. Their antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was highly dependent on the Cu/Fe ratio. Among them, CuFe-LDH-3 (Cu/Fe = 3:1) demonstrated the highest antibacterial efficacy, achieving 100 % inhibition at 0.05 mg/mL for S. aureus and 0.5 mg/mL for E. coli. This was attributed to the synergistic action of the released Cu2+ and Fe3+ ions and peroxidase-mimicking ROS generation. Moreover, CuFe-LDH-3 was incorporated into a hydroxypropyl methylcellulose ((HPMC)/hyaluronic acid(HA)/glycerol(Gl) hydrogel matrix to develop a thermo-sensitive composite hydrogel (CuFe-LDH/HHG). The resulting composite hydrogel exhibited thermo-sensitive sol-gel transition between 34 and 36 degrees C. In addition, the 0.1 % (W/V) CuFe-LDH/HHG hydrogel displayed excellent antibacterial activity, good biocompatibility, and endothelial cell proliferation promotion. This study presents a novel thermo-sensitive antibacterial composite hydrogel system with remarkable antibacterial properties and biocompatibility, highlighting its potential for wound healing and biomedical applications.