Antibacterial and Cytotoxic Efficacy of Extracellular Silver Nanoparticles Biofabricated from Chromium Reducing Novel OS4 Strain of Stenotrophomonas maltophilia

Abstract

Biofabricated metal nanoparticles are generally biocompatible, inexpensive, and ecofriendly, therefore, are used preferably in industries, medical and material science research. Considering the importance of biofabricated materials, we isolated, characterized and identified a novel bacterial strain OS4 of Stenotrophomonas maltophilia (GenBank: JN247637.1). At neutral pH, this Gram negative bacterial strain significantly reduced hexavalent chromium, an important heavy metal contaminant found in the tannery effluents and minings. Subsequently, even at room temperature the supernatant of log phase grown culture of strain OS4 also reduced silver nitrate (AgNO3) to generate nanoparticles (AgNPs). These AgNPs were further characterized by UV–visible, Nanophox particle size analyzer, XRD, SEM and FTIR. As evident from the FTIR data, plausibly the protein components of supernatant caused the reduction of AgNO3. The cuboid and homogenous AgNPs showed a characteristic UV-visible peak at 428 nm with average size of ∼93 nm. The XRD spectra exhibited the characteristic Bragg peaks of 111, 200, 220 and 311 facets of the face centred cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. From the nanoparticle release kinetics data, the rapid release of AgNPs was correlated with the particle size and increasing surface area of the nanoparticles. A highly significant antimicrobial activity against medically important bacteria by the biofabricated AgNPs was also revealed as decline in growth of Staphylococcus aureus (91%), Escherichia coli (69%) and Serratia marcescens (66%) substantially. Additionally, different cytotoxic assays showed no toxicity of AgNPs to liver function, RBCs, splenocytes and HeLa cells, hence these particles were safe to use. Therefore, this novel bacterial strain OS4 is likely to provide broad spectrum benefits for curing chromium polluted sites, for biofabrication of AgNPs and ultimately in the nanoparticle based drug formulation for the treatment of infectious diseases.

Biosynthesis of Au, Ag and Au&ndash;Ag bimetallic nanoparticles using protein extracts of <em>Deinococcus radiodurans</em> and evaluation of their cytotoxicity

“…4 Briefly, the NPs were placed in a dialysis bag that was suspended in an ultrapure water solution (40 mL). Then, a continuous release of the NPs was measured over a period of 48 h using inductively coupled plasma-optical emission spectroscopy (ICP-OES; Optima 8000DV; PerkinElmer Inc., Waltham, MA, USA).…”

“…[1][2][3] With the advancements in the field of nanotechnology, noble metallic NPs including gold nanoparticles (AuNPs), silver nanoparticles (AgNPs) or Au-Ag bimetallic NPs have demonstrated wide application potentials in antimicrobial agents, 4,5 diagnosis, 6 therapy, 6,7 biosensing, 8 drug delivery, 9,10 and industrial catalysis.…”

Effect of Incubation Time, CuSO4 and Glucose Concentrations on Biosynthesis of Copper Oxide (CuO) Nanoparticles with Rectangular Shape and Antibacterial Activity: Taguchi Method Approach

“…In contrast to the herbal type, biosynthesis of NPs by bacteria does not have the disadvantages of high polydispersity index (PDI) in NPs production due to the lack of multiple secondary metabolites including polyphenols and flavonoids [31]. In the case of bacterial approach for biosynthesis of NPs, it can utilize culture supernatant [32,33], bacterial biomass [34], cell-free extract [35], and bacterial derived components [36]. Therefore, in this study, we used culture supernatant as the extracellular approach of biosynthesis CuO NPs due to the simple recovery of NPs compared to the intracellular mode [37].…”

Application Of Nanotechnology In Agriculture And Food Industry, Its Prospects And Risks

“…The efficacy of AgNPs is dependent on particle size and shape and decreases with increasing particle size; it was found that truncated triangular particle shape showed greater "cidal" effect than spherical and rod shaped particles [130,131]. Antifungal properties of AgNPs have been exploited to a great extent against a broad range of human pathogens [132][133][134][135]. At present there is growing interest to utilize antifungal properties of AgNPs for plant disease management [136].…”