Controlled release of monodisperse silver nanoparticles via in situ cross-linked polyvinyl alcohol as benign and antibacterial electrospun nanofibers

A facile methodology was explored by using glutaraldehyde as a cross-linking reagent for in situ modification of polyvinyl alcohol (PVA) electrospun nanofibers doped with monodisperse silver nanoparticles (AgNPs) via the one-pot reactions. The hydroxyl groups along the PVA molecule chains can serve as both the reactive sites and stabilizers for AgNPs. Meanwhile, the cross-linking degree can be easily tuned by controlling the charged amounts of glutaraldehyde to obtain either partial or cured cross-linked PVA nanofibrous mats doped with AgNPs. It was revealed that such different cross-linking degrees could effectively control the release contents and rates of the embedded Ag to the surrounding aqueous solution. Furthermore, such release behavior was also found to be pH-responsive and acid-labile due to the formation of acetal groups during the cross-linking reactions. Besides both the partial and cured cross-linked PVA doped with Ag nanoparticles can still bear good antibacterial efficacy against S. aureus while have low cytotoxicity against mouse embryo fibroblasts (NIH3T3), human embryonic kidney cells (293T) and human histiocytic lymphoma cells (U937).