Author : Mohammad Irfan Ali, Gaurav Sharma, Manoj Kumar, Nakuleshwar Dut Jasuja, Rajgovind

The present study explores biological synthesis of ZnO nanoparticles (ZnO NPs) using the cell free aqueous extract of Spirulina platensis. Biosynthesized ZnO NPs were characterized by UV-Vis spectroscopy, SEM, TEM, XRD and FTIR studies and finally tested for antibacterial activity. Bio-synthesis using extract of S. platensis showed the formation of well scattered, highly stable, spherical ZnO NPs with an average size of 40-50 nm. The size and morphology of the nanoparticles were confirmed by SEM and TEM analysis. FTIR and UV-Vis spectra showed that proteins and peptides are mainly responsible for the formation and stabilization of ZnO NPs. Furthermore, the synthesized nanoparticles exhibited good antibacterial activity against pathogenic gram-negative i.e. Escherichia Coli- MTCC-9721, Proteus vulgaris- MTCC-7299, Klebsiella pneumonia- MTCC-9751 and gram-positive i.e. Staphylococcus aureus- MTCC-9542, S. epidermidis- MTCC- 2639, Bacillus cereus- MTCC-9017 bacteria. The ZnO NPs had shown maximum zone of inhibition (ZOI) i.e. 34.8±1.65 in P. vulgaris. Use of such a biological method provides a simple, cost-effective alternative template for the synthesis of nanomaterials in a large scale that could be great use in biomedical applications.

Keywords: Zinc nanoparticles, Spirulina platensis, Antibacterial activity, and Biosynthesis

Article published in International Journal of Current Engineering and Technology, Vol.5, No.4 (Aug-2015)