A facile green synthesis route to silver nanoparticles using cyanobacterium Nostoc carneum and its photocatalytic, antibacterial and anticoagulative activity

A facile green synthesis method for the synthesis of silver nanoparticles (AgNPs) using dried biomass of a cyanobacterium, Nostoc carneum has been developed by reduction of aqueous solution of silver nitrate. The as-synthesized silver nanoparticles were characterized using ultraviolet-visible (UV-Vis) spectrophotometry, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS) studies confirmed the formation of polydispersed, quasi-spherical shaped silver nanoparticles with 4-22 nm size stable beyond similar to 90 days. Fourier transform infrared (FTIR) analysis indicated the presence of phytochemicals on the AgNPs surface which served as both reducing and capping agents. The powder X-ray diffraction (XRD) study indicated a face-centered cubic crystalline structure of the nanoparticles. The as-synthesized silver nanoparticles exhibited a rather high photocatalytic activity for the degradation of two water soluble dyes, methylene blue (MB) and 2-Nitroaniline (2-NA) with degradation efficiency 92.5% and 82.5%, respectively. Kinetic study of the degradation reaction revealed the rates to be pseudo-first order in nature with rate constants 0.1138 min(-1) and 0.0443 min(-1) for MB and 2-NA, respectively. Significant anti-bacterial activity of the AgNPs against four selected pathogenic bacterial strains was observed. Further, the phytomolecule loaded AgNPs exhibited anticoagulant activity by inhibiting the human blood clotting for > 4 h.