Bio-synthesis of silver nanoparticles with the brackish water blue-green alga Oscillatoria princeps and antibacterial assessment

Abstract

This study describes the morphology of a filamentous non-heterocystous blue-green alga (cyanobacterium) Oscillatoria princeps isolated from the Bhabakundalswara sea mouth, its use in biogenic synthesis of silver nanoparticles (AgNPs), along with antimicrobial studies using multidrug resistant (MDR) methicillin-resistant strains of Staphylococcus aureus (MRSA), Streptococcus pyogenes and Escherichia coli, isolated from clinical samples. The synthesized O. princeps -AgNPs were characterized with UV–visible spectrometry, scanning electron microscopy (SEM), X-ray diffraction (XRD), dynamic light scattering analysis (DLS) and Fourier transform infrared spectroscopy (FT-IR) analyses. The synthesized AgNPs had remarkable antibacterial activities against MDR strains of MRSA, S. pyogenes and E. coli with the inhibitory zone sizes, 14–16 mm as recorded from agar well diffusion method, while MIC values were 100, 80, 60 µg/ml, for the respective cited bacterial species. Thus, O. princeps -AgNPs in future would be druggable antibacterials.