Biosynthesis of silver and gold nanoparticles using cyanobacteria, their pharmaceutical and industrial applications.

Nanotechnology has become a fast-growing field, and to prepare metallic nanoparticles for clinics or chemical establishments, it is mandatory that a cost-effective, eco-friendly technique be developed, using all nontoxic and renewable resources. This review presents biogenesis of silver and gold nanoparticles based on the utilization of natural metabolic routes leading to the synthesis of these nanoparticles mediated by cyanobacteria. These photosynthetic microorganisms become highly efficient 'bio-factories', for metal ion reduction and stabilization on the resulting biosynthesis of nanoparticles in a one-step manner. Significant attention has been directed towards the potent antimicrobial potential of these biogenic nanoparticles against numerous pathogenic multidrug resistant bacteria and fungi, as well. Furthermore, this review also provides a summary of recent understanding on mechanisms of their activities, as well as their huge potentialities for use in a variety of industrial/medical sectors, such as cleansing uses, wastewater remediation and industrial utilities as advanced materials. Indeed, the laboratory-scale biosynthesis with an oxygen-evolving photosynthetic prokaryote, the cyanobacterium, is user-friendly, but it could be scaled up for several industrial processes.