Photosynthetic microbes in nanobiotechnology Applications and perspectives

Photosynthetic microbes like brown algae, red algae, green-algae and blue-green algae (cyanobacteria) are utilized extensively for various commercial and industrial purposes. However, in recent time, their application has shifted to
nanotechnology. The synthesis of metal nanoparticles using algal resources is known as Phyconanotechnology. Due
to various advantages of the photosynthetic microbes such as presence of bioactive molecules, scalability, high metal uptake and cultivability, these microbes form ideal sources for nanoparticle synthesis. The green synthesis of
nanoparticles is a non-toxic and environment-friendly alternative compared to other hazardous chemical and physical
routes of synthesis. Several species of algae are explored for the fabrication of metal and metal oxide nanoparticles.
Various physical characterization techniques collectively contribute in defining the surface morphology of nanoparticles and the existing functional groups for bioreduction and stability. A wide range of nanostructured metals like gold, silver, copper, zinc, iron, platinum and palladium are fabricated using algae and cyanobacteria. Due to the unique properties of the phycogenic nanoparticles, biocompatibility and safety aspects, all of these metal nanoparticles have their applications in facets like infection control, diagnosis, drug delivery, biosensing and bioremediation. Herein, the uniqueness of the phycogenic nanoparticles along with their distinctive antibacterial, antifungal, antibiofilm, algaecidal, antiviral, anticancer, antioxidant, antidiabetic, dye degradation, metal removal and catalytic properties are featured. Lastly, this work highlights the various challenges and future perspectives for further exploration of the biogenicmetal nanoparticles for development of nanomedicine and environmental remediation in the coming
years.