In situ synthesis of silver nanoparticles on silk: producing antibacterial fabrics

Herein, we explored an effective method for preparing silver nanoparticles (Ag NPs)-coated antibacterial silk fabrics. In particular, using amino acids and cellulose from silk as reducing agents and silver nitrate as a precursor, Ag NPs were synthesised in situ on the surface of silk without requiring additional reducing agents and catalysts. The surface morphology and chemical composition of the involved samples were characterised using techniques such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Notably, silk and silk precursors (silkworm cocoons, silk fibers and sericin) could be used for in situ Ag NPs synthesis. Furthermore, the antibacterial properties of the samples were evaluated against Escherichia coli—a Gram-negative bacterium—as a model, demonstrating an impressive antibacterial rate of up to 99.91%. In addition, we investigated the water absorption behaviour of the samples at 25 °C by assessing their moisture regain, water retention value and vertical wick height. The results indicated that the Ag NPs coating did not damage the water absorption performance of the involved silk. Finally, we compared the fabric performance before and after treatment using a universal testing machine and colorimeter. The results showed that the mechanical properties of the fabrics with the Ag NPs coating did not substantially change with treatment, but the fabrics became more yellowish. Overall, this research has notable application potential in the field of antibacterial fabrics.