Extracellular Biosynthesis of AgNPs by the Bacterium Proteus mirabilis and Its Toxic Effect on Some Aspects of Animal Physiology

The development of a reliable green chemistry process for the biogenic synthesis of nanomaterials is an important aspect of current nanotechnology research. Silver nanoparticles (AgNPs) have been used as antimicrobial and disinfectant agents. However, there is limited information about its toxicity. Therefore, this study focused on the biosynthesis of AgNPs by the bacterium Proteus mirabilis and on determining its preliminary toxic effect on some aspects of animal physiology. A green method for the synthesis of AgNPs using culture supernatant of Proteus mirabilis has been developed in this study and the synthesized AgNPs were characterized by several techniques. The AgNPs showed a maximum absorbance at 445 nm on ultraviolet-visible spectra. The presence of proteins was identified by Fourier transform-infrared spectroscopy. The reduction of Ag+ to elemental silver was characterized by X-ray spectroscopy analysis. The transmission electron micrograph revealed the formation of polydispersed nanoparticles of 5 - 45 nm. The AgNPs were evaluated for their toxic effect on pregnant female albino rat. The result showed that liver enzymes (AST and ALP) were decreased significantly in the group treated with AgNPs. Mean corpuscular hemoglobin concentration also showed significant increase.