Preparation and Properties of Antibacterial and Antioxidant NO Releasing Hydrogels

Bacterial infection seriously endangers patients' health. Thus, it is imperative to develop highly efficient antibacterial materials. In this study, antibacterial and antioxidant hydrogel with photothermal effect and nitric oxide (NO) gas-releasing property was designed and synthesized. The hydrogel was formed by crosslinking ε-polylysine and tannic acid using Fe³⁺ and glutaraldehyde and loading NO donor S-nitroso-N-acetyl-DL penicillamine (SNAP). The Fe₉-TA₂₀ hydrogel shows high photothermal effect and the temperature of the hydrogel can reach 43.8 ℃ within 10 min under 1 W/cm² near-infrared irradiation. Additionally, the NO-Fe₉-TA₂₀ hydrogel shows effective NO-release activities. Under visible light and at 37 ℃, the amount of NO released from the hydrogel reach 36.48 μmol/L within 3 h. Benefitting from the synergetic effect of cations of ε-poly-L-lysine (EPL) and the released NO, NO-Fe₉-TA₂₀ hydrogel exhibits antibacterial activity (> 99.9%) towards Staphylococcus aureus, and can effectively scavenge 1,1-dipheny-2-picrylhydrazyl (DPPH) free radicals (> 84.3%), which may protect cells from oxidative stress damage. This study may provide a new approach for bacterial infections treatment.