Recent progress in algae-mediated silver nanoparticle synthesis

The use of silver nanoparticles (AgNPs) in many consumer products is expected to increase in the future due to their multifaceted properties. With the increasing demand for AgNPs, manufacturers are focusing more on exploring various methods for synthesizing AgNPs that are safer, cost-effective, and scalable. Synthesis of AgNPs using biological processes is advantageous over physical and chemical methods, primarily due to low cost and being free of hazardous chemical reagents. Among the biological processes, various groups of algae have been explored for the synthesis of AgNPs. Different biogenic substances present in the algae serve as excellent reducing and capping agents for the synthesis of NPs. Moreover, in comparison to plants and other microorganisms, algae are easy to maintain and show mass multiplication. In this review, state-of-the-art information has been collected regarding the usage of different groups of algae for the synthesis of AgNPs, their physico-chemical properties, mechanism of synthesis, and bioactivity in detail. One of the applications of AgNPs i.e., antimicrobial activity, is discussed in detail. Further, a conceptual framework regarding various techniques used for characterization of nanoparticles is described.