A hydrogel based on Fe(ii)-GMP demonstrates tunable emission, self-healing mechanical strength and Fenton chemistry-mediated notable antibacterial properties

Abstract

Supramolecular hydrogels serve as an excellent platform to enable in situ reactive oxygen species (ROS) generation while maintaining controlled localized conditions, thereby mitigating cytotoxicity. Herein, we demonstrate hydrogel formation using guanosine-5′-monophosphate (GMP) with tetra(4-carboxylphenyl) ethylene (1) to exhibit aggregation-induced emission (AIE) and tunable mechanical strength in the presence of divalent metal ions such as Ca²⁺, Mg²⁺, and Fe²⁺. The addition of divalent metal ions leads to structural transformation in the metallogels (M-1_GMP). Furthermore, the incorporation of Fe²⁺ ions into the hydrogel (Fe-1_GMP) promotes the Fenton reaction that could be upregulated upon adding ascorbic acid (AA), demonstrating antibacterial efficacy via ROS generation. In vitro studies on AA-loaded Fe-1_GMP demonstrate excellent bacterial killing efficacy against E. coli, S. aureus and vancomycin-resistant enterococci (VRE) strains. Finally, in vivo studies involving topical administration of Fe-1_GMP to Balb/c mice with skin infections further suggest the potential antibacterial efficacy of the hydrogel. Taken together, the hydrogel with its unique combination of mechanical tunability, ROS generation capability and antibacterial efficacy can be used for biomedical applications, particularly in wound healing and infection control.