Chitosan-mediated silver nanoparticles enhance the interfacial properties and multi-functional performance of silk

Surface and interface engineering for producing advanced materials with well-defined physicochemical features and sustained biological activities remains an arduous goal for scientists worldwide. This study presents a biopolymeric-mediated interfacial approach to functionalize a novel green synthesized Ag nanoparticle for tailoring surface and biological properties of silk. Ag nanoparticles are in-situ synthesized in garlic essential oil nanoemulsion (Ag-GNE) for the first time, followed by interfacial stabilization with chitosan (Ag-GNE-CS), and used for immediate silk surface coating. Characterizations of silk fibers in terms of its chemical compositions, morphology, topography, and interfacial chemical states, indicate successful incorporation of Ag nanoparticles on the surface of fibers. The silk treated with Ag-GNE-CS system exhibits outstanding antimicrobial effect upon E. coli, S. aureus, and A. niger. Moreover, it shows antioxidant potential through hydroxyl and superoxide free radicals scavenging. This treated silk also has UV-protective capacity with UPF 50⁺. In addition, the non-significant difference in the functional features of the treated silk before and after washing signified the advantage of chitosan-mediated interfacial modification in stabilizing Ag nanostructure and promoting its interfacial interaction with silk. Furthermore, ICP-OES results reflect that the chitosan-stabilized nanostructure controls Ag leaching throughout 15 washing cycles with less initial leakage of loosely bound nanoparticles, which reveals the environmentally friendly aspect of the formulation. This study proposes a safe, sustainable, and scalable design for functional nano-interfaces, while also providing a promising idea for next-generation healthcare and protective materials through surface and interface nano-engineering.