Conductive hydrogels with hierarchical biofilm inhibition capability accelerate diabetic ulcer healing

Abstract

Diabetic ulcers (DUs) are characterized by massive biofilm formation, long-term inflammatory infiltration, and difficulty in healing. Electrical stimulation (ES) applied through hydrogel dressings is promising to treat DUs, but the development of advanced hydrogels with stable conductivity and effective antibacterial properties remains challenging. Loading antibiotics in hydrogels by absorption is prone to the initial burst release, which is associated with frequent dressing changes and bacterial resistance development. Herein, antibacterial terbium ions are incorporated into the hydrogel network by coordination interactions for sustainable release. Agarose and zwitterions are used to prevent protein absorption and bacterial adhesion due to their strong hydration ability. The combination of the antifouling components and bactericidal terbium ions in the hydrogel results in a tremendous antibacterial effect, which completely inhibits biofilm formation by Staphylococcus aureus and Escherichia coli. Polypyrrole is also covalently grafted to the hydrogel network, providing stable and biomimetic conductivity. When ES is applied through the hydrogel, the antibacterial hydrogel controls the inflammation induced by infection and the applied ES helps DUs pass the proliferation stage, and thus accelerates wound healing.