Electrospun AgNPs-polylactate nanofibers and their antimicrobial applications

Abstract

Silver nanoparticles (AgNPs) have been one of the most significant nanoparticles due to their interesting characteristics, such as high antimicrobial activity. Thus, they have been applicable for wound dressing, protective textiles and tissue scaffold. In the current study, novel polylactate copolymer was prepared via condensation of lactic acid (LA) and methacrylic acid (MAA) at molar ratio of 95:5, and then the produced copolymer was subjected to free radical polymerization in the presence of N, N-methylene diacrylamide (MDA) as a cross-linking agent. AgNPs were synthesized utilizing chitosan (Cs) as reductive and stabilizing agent. The generation of AgNPs was proved with UV–Vis absorbance spectra, and transmission electron microscopy (TEM) which displayed different morphologies of AgNPs relying on the heating period. The chemical formula of the polylactate sodium salt (PLS) polymer was verified with FT-IR and 1H NMR spectra. Cs-AgNPs nanohybrid was coated into an electrospun nanofibrous membrane of the cross-linked polylactate calcium salt (PLCS) to create stable polyelectrolyte complex (PEX) nanofiber-based composites with high antimicrobial activity. The produced nanohybrids were studied by X-ray diffraction (XRD), energy-dispersive X-ray analyzer (EDX), scan electron microscopy (SEM), elemental mapping and Fourier-transform infrared spectroscopy (FT-IR). AgNPs were effectively immobilized onto the PEX nanofiber-based composite, whilst there was complex generated among the electrospun PLCS and the Cs-AgNPs nanohybrid. The developed nanofibrous mats demonstrated an improved saline absorbance in the presence of AgNPs. AgNPs exhibited a homogeneous dispersion and high deposition density on the surface of nanofibers demonstrating a nanoparticle size of 7–23 nm. In addition, the silver immobilized PLCS fibers showed an improved absorbance of 0.85% (w/v) saline solution compared to blank fibers. PEX displayed high antimicrobial efficiency against gram positive and gram negative bacterial pathogens with satisfactory permeability of water vapor in the range necessary for treating wounds.