 14 out of 16 tested strains of cyanobacteria and microalgae were able to biosynthesize silver nanoparticles, AGNPS, using two procedures, with TEM analysis showing that the nanoparticles were embedded within an organic matrix and varied in shape and sizes. The antibacterial activity of AGNPS was confirmed in all but one strain of cyanobacterium. This article was authored by Vijay Patel, David Berthold, Praveen Paranik and others.