Algal-derived nanoparticles and their antibacterial potential: Current evidence and future prospectives

Green nanotechnology provides efficient solutions for converting biological systems to green approaches through nanomaterial synthesis and thus preventing any associated toxicity. Green nanoparticle (NP) synthesis involves the use of biological sources for synthesis of metallic NPs for pharmaceutical and biomedical applications in an eco-friendly and comparatively economical manner. Nanotechnology is a promising technology with a wide range of pharmaceutical applications in the modern world because it provides a higher surface area (SA) to volume (Vol) ratio. Compared to chemically synthesized NPs, algal-based NPs have recently received increasing attention from researchers worldwide as potential agents to treat and inhibit infections caused by microbial pathogens resistant to antibiotics. Algae produce various bioactive compounds such as chlorophyll, phycobilins, phenolics, flavonoids, glucosides, tannins, and saponins that can be used as therapeutic agents. Metallic NPs exert greater toxic effects on their targets than their macroscopic counterparts. Both macroalgae and some microalgae are used to synthesize metallic NPs that exhibit antimicrobial activity. The synthesis of algal-based NPs may provide potential drug candidates for use in nanomedicine against microbial diseases. To date, many studies have been conducted on algal-based NPs and their potential antimicrobial and antifungal activities. Therefore, in this review we have focused on the green synthesis of different NPs using algae and their therapeutic potential with reference to their antimicrobial activity.