Abstract : Introduction: The all-around attraction towards Silver Nanoparticles (AgNPs) is fairly due to its
biocompatibility, so that it can be used in therapeutics and diagnostics. In order, to harvest them with
such unique properties, there is this pressing urge to develop a cheaper and an eco-friendly process without
the use of toxic chemicals. In lieu of this, this study was taken up to optimise the reactant parameters
required to obtain a maximum yield of AgNPs using cell-free culture extract of bacteria obtained from
Materials and Methods: Bacterial strains were procured from routine clinical samples. Bacterial biomass
production was done in liquid media which was further harvested and lysed. The supernatent(E) in
varying concentrations was then mixed with varying concentrations of 1mM AgNO3(M) (E:M ratio).
Visual examination for colour change and confirmation by UV-Spectrophotometry (UV-S) was done and
AgNPs were separated by Ultra-centrifugation. The synthesised NanoParticles(NPs) were characterized by
Scanning Electron Microscopy(SEM) and X-Ray Diffraction(XRD) studies for confirmation.
Results: The UV-S showed an absorption value at 450nm as 1.3 in 1E:1M for Escherichia coli followed
by Abs: 1.0 for Staphylococcus aureus in 1E:1M ratio. The Dynamic Light Scattering study showed that
the particles obtained in the study were predominantly in the acceptable range of 127.35nm & 90.96nm
for Staphylococcus aureus & Escherichia coli respectively. When observed under SEM, the synthesised
particles were found to be agglomerated, but polydispersed and crystalline in nature. In XRD study a
maximum peak was obtained at 38.22 which confirmed the crystalline structure synthesized from bacterial
extract as AgNPs when compared with JCPD standards.
Keywords: Nanotechnology, Nanoparticles, Silver, Bacteria.