Mussel Inspired In Situ Preparation of Antibacterial Silver Nanoparticles by DOPA‐Containing Silk Fibroin

Silver nanoparticles (AgNPs) attract a great deal of attention for potent antibacterial capacity, but their use is challenged by limited stability. Inspired by the adhesive and redox properties of the mussel foot proteins containing L‐3,4‐dihydroxyphenylalanine (DOPA), a facile strategy for in situ synthesis of AgNPs using DOPA‐containing fibroin is developed. Tyrosine residues in fibroin are transformed into DOPA via biomimetic synthesis method with content of 0.55 mol%. In situ synthesis generates stable and small AgNPs through DOPA bound in fibroin as a reducing and stabilizing agent. Narrow size distribution with average diameter of 20 nm and excellent monodispersity are obtained. Cross‐linking with lysine increases the content of β‐sheet to form hydrogel and achieves gradual release of silver. The material exhibits excellent antibacterial properties against Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli bacteria. It can be potentially applied in biological and medical fields to treat bacterial infections. Inspired by mussel foot proteins, silver nanoparticles (AgNPs) are in situ synthesized using L‐3,4‐dihydroxyphenylalanine (DOPA) containing fibroin. Tyrosine residues in fibroin are transformed into DOPA via biomimetic synthesis. In situ synthesis generates stable and small AgNPs through DOPA bound in fibroin as a reducing and stabilizing agent. Cross‐linking with lysine facilitates formation of hydrogel. The material exhibits excellent antibacterial properties.