Synthesis of nano‐silver from Navicula cincta and the evaluation of its antimicrobial activity

Abstract

Green synthesis of silver nanoparticles is cost effective and encourages the use of non-toxic chemicals. The biological sources of reductants have trouble free protocols and when applied for human health associated field, is an easy approach for maintaining aseptic environment during the synthesis of nanoparticles. Microalgae are used as a source of natural colours and exhibit extensive applications as natural colorants in nutraceuticals, cosmetics and pharmaceutical industries. The use of Navicula cincta microalgae in the biogenic synthesis of silver nanoparticles is unexplored and underexploited. In this work, silver nanoparticles synthesised using algal extract by sunlight method were characterised by UV-Visible spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy and particles size analyser. The antimicrobial activity of nanosilver against seven bacteria, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Shigella flexneri, Vibrio cholera and Salmonella typhi and four fungi Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus and Rhizopus stolonifer are investigated using agar well diffusion technique and compared with standard antibiotics namely Chloramphenicol and Nystatin.