Silver-Functionalized Silk Fibroin Films: Development and Characterization for Antibacterial Wound Dressings

In this work, an in situ UV-assisted photoreduction was used to functionalize silk fibroin films with silver nanoparticles in order to develop antibacterial devices for wound healing applications. The process showed high efficiency (~80%) in terms of reacted silver precursor. The effects of the silver treatment on fibroin macromolecule were evaluated in function of the process parameters in terms of chemical structure, thermal and mechanical properties, swelling behavior, resistance to degradation and antibacterial activity. Silver functionalization significantly improved the mechanical properties of the films, with Young’s modulus increasing from 0.23 ± 0.04 MPa (methanol-treated samples) to 7.26 ± 0.46 MPa (silver-functionalized samples). In parallel, a marked reduction in swelling degree was observed (from ~360–420% to ~60%), indicating enhanced structural stability. The treated films also exhibited improved resistance to degradation over 7 days under physiological conditions. From a functional perspective, the materials showed strong antibacterial activity, with up to 97–98% reduction in bacterial proliferation for Pseudomonas aeruginosa and Escherichia coli, and up to 93% for methicillin-resistant Staphylococcus aureus. Overall, the results demonstrate that silver functionalization process improves the structural stability of silk fibroin while conferring sustained antibacterial activity, thus supporting their potential application as antimicrobial dressings for the treatment of superficial and low-exudate wounds.