Optimisation of Reactant Concentration in Biosynthesis of Silver Nanoparticles using Pathogenic Bacteria Isolated from Clinical Sources and their Characterisation: A Recent Study

Introduction: The overall attraction of Silver Nanoparticles (AgNPs) is due to their biocompatibility, which allows them to be used in therapeutics and diagnostics. To harvest them with such unique properties, there is a pressing need to develop a less expensive and more environmentally friendly process that does not involve the use of toxic chemicals. Instead, the purpose of this study was to optimize the reactant parameters required to achieve the highest yield of AgNPs using cell-free culture extract of bacteria obtained from clinical sources.

Materials and Methods: Bacterial strains were obtained through routine clinical samples. Bacterial biomass was produced in liquid media, which was then harvested and lysed. The supernatant (E) in varying concentrations was then mixed with varying concentrations of 1mM AgNO3 (M) (E:M ratio). UV-Spectrophotometry (UV-S) was used to confirm the colour change, and AgNPs were separated using ultracentrifugation. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) studies were used to confirm the synthesised Nano Particles (NPs).

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 revealed that the particles obtained in the study were mostly within the acceptable ranges of 127.35nm and 90.96nm for Staphylococcus aureus and Escherichia coli, respectively. The synthesised particles were found to be agglomerated, but polydispersed and crystalline when examined under SEM. When compared to JCPD standards, an XRD study yielded a maximum peak at 38.22, confirming the crystalline structure synthesised from bacterial extract as AgNPs.