Safe and Effective Ag Nanoparticles Immobilized Antimicrobial NanoNonwovens

Silver nanoparticles (AgNPs) with large surface-to-volume ratio have been widely studied as a valuable material for their strong antimicrobial effect. However, the practical applications of AgNPs in health care and water purification are often hampered by the concern of their toxicity and possibility of introduction of secondary pollution. Here, we present a novel strategy to produce a safe and effective antimicrobial nanononwoven material by immobilizing AgNPs on a rigid polymer nanofibrous matrix through simple co-electrospinning of pre-prepaired AgNPs and polystyrene (PS). Distribution of the AgNPs on the surface of PS fibers was achieved by tuning fiber diameters during electrospinning. Atomic force microscopy (AFM) analysis revealed that the AgNPs distributed at the fiber surface were still covered by a layer of polymer, which inhibited their antimicrobial activity. UV/ozone treatment was thus employed to degrade the polymer coating without loosening the AgNPs, resulting in an active antimicrobial nonwoven against Gram-positive Staphylococcus xylosus. The mechanism based on cellular uptake of silver ions via close contact to the surface of AgNPs is proposed. The novel nanononwoven retains the enhanced antimicrobial activities from nanofeatured AgNPs without detectable AgNPs leaching, which holds great potential for safe and recyclable use.