Thermoresponsive and Self-Healing Hydrogel Based on Chitosan Derivatives and Polyoxometalate as an Antibacterial Coating

Hospital-acquired infections are a serious threat to the recovery of patients. To prevent such infections, an antibacterial coating is an effective method to eliminate bacterial colonization on healthcare-related surfaces. Herein, we report an antibacterial hydrogel composed of silver-containing polyoxometalate (AgP₅W₃₀ POM) and carboxymethyl chitosan (CMC). The silver ion is encapsulated inside the POM cage and demonstrates long-lasting bacteriostasis after repeated exposure to both Gram-positive and Gram-negative bacteria. The chemical structure of chitosan derivatives, as well as the concentration and pH, is studied to tune the mechanical properties of the hydrogel. The hydrogel undergoes a gel-sol transition above the critical temperature and possesses self-healing ability. This hydrogel can be readily coated on the surface of versatile bulk materials, which is especially convenient for porous objects and resists the growth of Staphylococcus aureus, Escherichia coli, and methicillin-resistant S. aureus (MRSA). In summary, we envision that the AgP₅W₃₀-CMC hydrogel has great potential to serve as an antibacterial coating to decrease the prevalence of hospital-acquired infections.