Desertifilum sp. EAZ03 cell extract as a novel natural source for the biosynthesis of zinc oxide nanoparticles and antibacterial, anticancer and antibiofilm characteristics of synthesized zinc oxide nanoparticles.

Abstract

The use of cyanobacterial cell extracts for the synthesis of zinc oxide nanoparticles (ZnO NPs) seems to be superior to other methods of synthesis because of its a green, environmentally friendly and low-cost approach. In this study, the cell extract of a newly characterized cyanobacterial strain Desertifilum sp. EAZ03 was used for the biosynthesis of ZnO NPs. The antimicrobial, antibiofilm and anticancer activities of the biosynthesized ZnO NPs (hereinafter referred to as CED-ZnO NPs) were examined as well. UV-Vis spectroscopy analysis of CED-ZnO NPs showed an absorbance band at 364nm, and powder X-ray diffraction analysis confirmed the purity of the synthesized nanoparticles. The analyses of scanning electron microscopy and transmission electron microscopy images revealed that CED-ZnO NPs were rod-shaped with a size of 88nm. The study of the biological features of CED-ZnO NPs showed a significant antimicrobial potential against the bacterial strains tested. CED-ZnO NPs were able to impede the biofilm formation by Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa up to 80%, 89% and 85%, respectively. The nanoparticles also showed 69%, 70% and 62% degrading activity against S. aureus, E. coli and P. aeruginosa 1-day-old biofilms, respectively. The antibiofilm activity of the synthesized nanoparticles was investigated by confocal laser scanning microscopy. The MTT assay showed that CED-ZnO NPs, at a concentration of 100μg/ml, had less cytotoxicity towards normal lung (MRC-5) cells, at the half, compared to cancerous lung alveolar epithelial (A549) cells. The minimum inhibitory concentration and minimum bactericidal concentration values of CED-ZnO NPs against E. coli, P. aeruginosa and S. aureus were 1500, 2000 and 32μg/ml, and 2500, 3500 and 64μg/ml, respectively. The multifunctional CED-ZnO NPs seem to be promising for possible applications in the therapeutic and pharmaceutical industries. This study proposes a new approach for the biosynthesis of zinc oxide nanoparticles using a newly characterized cyanobacterial strain Desertifilum sp. EAZ03. The considerable antimicrobial, antibiofilm and anticancer activities of the biosynthesized zinc oxide nanoparticles further emphasize the emerging role of microbial systems in the green synthesis of metal oxide nanoparticles.