Rapid in-situ green synthesis and antibacterial properties of silver nanoparticles

In-situ green synthesis of silver nanoparticles (AgNPs) using hydroxypropyl-methylcellulose (HPMC) as a reducing and stabilizing agent is presented in this paper. A simple solution-casting method is used for preparing nanocomposite films. The reduction of silver ions to silver elementary particles was completed when the alkaline pH was maintained. The initial confirmation of AgNPs was visualized by the brown color of the prepared solution and later confirmed by the surface Plasmon resonance peak obtained from the UV-visible absorption study. X-ray diffraction measurement study revealed the crystalline nature of the AgNPs with FCC structure. The uniform distribution of AgNPs in the HPMC matrix is witnessed by Scanning electron microscope. The spherical shape of the prepared AgNPs is observed by transmission electron microscopic images with an average size of 11 nm. Dynamic light scattering experiment exposed the hydrodynamic size distribution and good stability of AgNPs. Thermogravimetric analysis showed high thermal stability of nanocomposites. Mechanical studies showed increased elongation at break and tensile strength of the prepared nanocomposites. Dielectric constant and dielectric loss were ascertained to decrease with an increase in frequency. Further, the antibacterial activity study showed an excellent activity of AgNPs in contrast to human bacterial pathogens viz., Staphylococcus aureus and Escherichia coli.