Green Synthesis and Characterization of Silver Nanoparticles with High Antibacterial Activity Using Cell Extracts of Cyanobacterium <i>Pseudanabaena/Limnothrix</i> sp. oleh Dimitra Karageorgou, Panagiota Zygouri, Theofylaktos Tsakiridis, Mohamed Amen Hammami, Nikolaos Chalmpes, Mohammed Subrati, Ioannis Sainis, Konstantinos Spyrou, Petros Katapodis, Dimitrios Gournis, Haralambos Stamatis