Mycosynthesis, Characterization and Evaluation of Therapeutic Potentials of Silver Nanoparticles

Abstract

Nanotechnology is an interdisciplinary field which deals with the manufacture and manipulation of objects at nanoscale from 1 to 100 nm sizes. Among various nanomaterials, metallic nanoparticles are of extreme importance due to their various applications in diagnostics and therapeutics. Silver nanoparticles (AgNPs) have been well characterized in relation to their importance in recent years. There are different methods of synthesis for these nanoparticles including physical, chemical and biological methods. Biological methods are nowadays preferred over other methods due to absence of harmful materials involved in the synthesis procedures. In this study, silver nanoparticles have been biologically synthesized by using Alternaria tenuissima as a biological source for reduction of silver nitrate salt. Mycosynthesis was adopted as a method of choice due to the presence of excessive active biological substances including secretary enzymes that act as catalyst in the bio-reduction reaction. After confirmation of synthesis by color change in reaction mixture, further characterization of newly synthesized AgNPs was performed by evaluation of visual spectrum obtained by UV/Vis spectrophotometry which showed spectrum peak around 430 nm. Furthermore, elemental analysis of particles was recognized by XRF and EDS analysis, showing the presence of silver element in the sample reaction mixture and purified nanoparticles samples respectively. Presence of amine groups of proteins was showed by FTIR analysis, depicting the fact that the particles in reaction mixture are stable in nature. XRD pattern was analyzed for characterizing the crystalline nature of the particles, which reported the face centered cubic nature of AgNPs. Average diameter, morphology and particle size distribution was measured by SEM analysis. Anti-oxidant activity of AgNPs was estimated and Abstract XXIV compared with ascorbic acid by DPPH assay which showed significant increase in free radical scavenging ability with increasing concentration of AgNPs. Anti bacterial activity of AgNPs was evaluated against methicillin resistant staphylococcus aureus (MRSA) by disc diffusion assay, which indicated visible inhibition zone of cultured bacteria on nutrient agar. Similarly, fungicidal ability of AgNPs was checked against two fungal species, Fusarium oxysporium and Fusarium verticillioides. Cytotoxicity of AgNPs on cancerous cells like MCF-7 and Huh-7 cell lines, was monitored by carrying out MTT Assays separately.