A comparison of silver nanoparticles made by green chemistry and femtosecond laser ablation and injected into a PVP/PVA/chitosan polymer blend

Abstract

Due to their antibacterial effect, silver nanoparticles (AgNPs) are attracting more and more attention for various applications in biomedicine. The production of nanomaterials from organometallic precursors requires the use of a capping agent that acts as a stabilizer and provides colloidal stability while preventing agglomeration and excessive growth. In this research, we studied the optical properties and antibacterial activity of AgNPs loaded in a blend of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and chitosan, which were used as capping agents to control the shape and size of the nanoparticles and to impart stability to the synthesized Ag nanomaterials. Characterization studies showed that the blend provides a uniform and controlled distribution of AgNPs inside the polymeric matrix without the addition of any more stabilizers. The mean particle size for green and laser-ablated AgNPs was found to be ~ 50 nm according to transmission electron microscopy (TEM) studies. Fourier transform infrared (FTIR) studies showed the presence of characteristic main peaks corresponding to the vibrational groups which characterize the prepared samples. The interactions between the AgNPs and the blend were marked by changes in the intensity of vibrational peaks and spectral positions. X-ray diffraction (XRD) confirmed the crystallographic modification within the PVP/PVA/chitosan matrix because of AgNPs filling. The change in the absorbance has been studied with the help of measured ultraviolet–visible spectroscopy (UV–Vis.) and therefore the optical band gap was calculated. The filling of AgNPs in the blend shows a broad peak at 427 nm because of the phenomenon of surface plasmon resonance (SPR) and its intensity increases with increasing filler concentration. The blend and the Ag nanocomposite showed remarkable antibacterial activity and caused a significant decrease in microbial growth (Escherichia coli) in 24 h. These outcomes demonstrate the suitability and promise of the nanocomposites for various applications, including biomedical labels, sensors, and detectors.