Influences of processing and sterilizing strategies on reduced silver nanoparticles in poly(vinyl alcohol) electrospun membranes: Optimization and preservation of antibacterial activity

Abstract

Silver cations (Ag+) and silver nanoparticles (AgNPs) are effective against a broad spectrum of bacteria. The contents and the size of reduced Ag are crucial to its antibacterial effect. Electrospinning was used in this study to stabilize the AgNPs by avoiding their agglomeration. Accordingly, the poly(vinyl alcohol) (PVA) was used for dispersion and reduction to increase the effective bacteriostatic dose of 15 wt% Ag+ (silver nitrate, AgNO3) to prepared fibrous membranes. Spinning solutions were also prepared following the optional heating pretreatment. The in situ reduction of Ag+ was enhanced in advance by electrospinning to prepare an Ag+/AgNP functionalized PVA fibrous membrane, which were then sterilized by post-operations of autoclaving and ultraviolet (UV) irradiation. Results showed that the presence of Ag+ cations can strengthen PVA crystallization and confirmed that electrospinning further reduced the Ag+ cations. Post-operations, especially autoclave sterilization, largely increased the size of the AgNPs. This increase resulted in antibacterial capability loss of the membranes. UV irradiation also revealed that the size of AgNPs was slightly increased but did not remarkably affect the antibacterial capability of the membrane. Therefore, the use of UV irradiation as the post-operation is recommended for sterilizing Ag+/AgNP functionalized PVA membranes to maintain their antibacterial function.