Sustainable phyco-fabrication of silver nanoparticles using Coelastrella terrestris and their multiple downstream applications

Algae-based route of nanoparticle synthesis is eco-friendly, simple, one-step, non-toxic and cost-effective. Algal extract of Coelastrella terrestris, was successfully used for phyco-fabrication of silver nano-particles (AgNPs) where this alga act as reducing and coating agent. The conditions were optimized for weight of dried algal biomass, conc. of AgNO3, ratio of algal extract: AgNO3 solution, pH, temperature, and time. It is observed that pH 10, at room temperature condition, with 10:90 ratio of algal extract: AgNO3 and 24 h of incubation time, is optimum for biogenic-fabrication of AgNPs. The fabricated Coel-AgNPs were characterized by UV-Vis, XRD, FTIR, SEM with EDX, HR-TEM with SAED and Zeta potential. The AgNPs synthesis is monitored with a significant peak observed in UV-Vis spectra at 420 nm. At higher pH level, AgNPs with a spherical shape were produced, which is validated by SEM and TEM with 28 nm and 52 nm in size, respectively. The purity of AgNPs has been verified by EDX with 82.79% purity. The crystalline nature of AgNPs is confirmed by XRD and functional groups which are involved in AgNPs synthesis are validated by FTIR spectra. The downstream applications of Coel-AgNPs were tested and it is found that these NPs can be effectively utilized as anti-cancerous nanodrug, antimicrobial agent and also found to have photocatalytic activity, making them suitable applicant for a wide range of biological and environmental applications.