Bio-approach: preparation of RGO-AgNPs on cotton fabric and interface with sweat environment for antibacterial activity.

Abstract

This study aims to develop a reduced graphene oxide (RGO)-silver nanoparticles (AgNPs) coating on the cotton fabric (CT) surface using photoreduction with a hydrothermal process and evaluate the antibacterial activity in a sweat environment. An ureolytic bacterium of Bacillus subtilis (HM475276) was used to generate ammonia from synthetic urine. RGO-AgNPs were synthesizedon the CT surface using a moderate dosage of 1% silver ammonium complex. The analytical study reveals that spherical-shaped AgNPs of 10-50nm size were uniformly anchored throughout the RGO sheet on the CT, further supported by X-ray photoelectron spectroscopic analysis (XPS). X-raypowder diffraction (XRD) and Energy-dispersive X-ray absorption spectroscopy (EDAX) elemental mapping confirmed Ag/AgCl formation on CT treated with sweat. The sustained release of Ag+ ions from the treated CT in the sweat solution was assessed by atomic absorption spectroscopy (AAS) and ranged from 2 to 8ppm, correlated with antibacterial activity. The agar diffusion and solution suspension method to demonstrate the combat bacterial species were greater on RGO-AgNPs-CT than sweat-treated CT due to the suppression of Ag+ ion release caused by the deposition of Ag/AgCl. Hence, sweat-treated RGO-AgNPs-CT proved to have higher inactivation activity (45min) than sweat-treated AgNPs-CT (60min) due to the RGO-Ag/AgCl serving photocatalyst influencing hydroxyl radical (OH·) formation under sunlight. The RGO-AgNPs-CT has confirmed that it retains antibacterial activity after passing the laundry durability test. Together, the results showed an opportunity for improved functional fabrics that are exceptional at combating bacterial pathogens and holding up well to laundry durability tests.