Green synthesis of silver nanoparticles from Thymus vulgaris and Sambucus nigra extracts in poly (vinyl alcohol) nanofiber matrix: In vitro evaluation

Abstract

In the current study, silver nanoparticles (AgNPs) green synthesized from Thymus vulgaris (Thyme) and Sambucus nigra (black elderberry) (BE) extracts and added into poly (vinyl alcohol) (PVA) solution to achieve antibacterial, biocompatible, and bioactive nanofibers through electrospinning technique. The absorbance peaks of AgNPs were found at 450 nm in the ultraviolet-visible (UV-Vis) spectrum, and AgNPs were found in (111) d-spacing in high-resolution transmission electron microscope (HRTEM). The average particle sizes were measured as 66.30 +/- 7.70 nm and 20.03 +/- 4.80 nm for ThymeAgNPs and BEAgNPs, respectively. 1 and 2 wt% content of the AgNPs were added into the PVA solution and electrospun at 9 kV voltage and 5 ml/hr flow rate. The fiber morphologies were investigated with the help of scanning electron microscopy (SEM) and HRTEM, and a decrease in the fiber diameter and the porosity of the fibers was obviously observed. Chemical bond analysis was done using Fourier transform infrared (FTIR), and the thermal behavior of the fiber was examined with a differential scanning calorimeter (DSC). X-ray diffraction (XRD) and HRTEM provide the presence of AgNPs in PVA nanofibers. According to antibacterial activity investigations the inhibition growth effect against Escherichia coli (E. coli) of PVA/ThymeAgNPs was 11.6 % higher than that of PVA/BEAgNPs. The cell cytotoxicity tests at different concentrations with L929 cells revealed better performance in PVA/Thyme nanofibers.