Biosynthesis of silver nanoparticles from the marine bacterium Marinobacter litoralis CARE V18 strain and evaluation of its antibacterial, antioxidant and acute toxicity properties using Zebrafish model

Biosynthesized silver nanoparticles (Ag-NPs) hold great potential for preventing, treating, diagnosing, and controlling diseases. The primary objective of this study is on marine halophilic bacteria ( Marinobacter litoralis CARE-V18) and their extracellular synthesis of Ag-NPs. The marine bacterial synthesized Ag-NPs is characterized using dynamic light scattering (DLS), zeta potential analysis (ZPA), fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The antibiofilm and antibacterial activity of the bacterially synthesized Ag-NPs against human bacterial pathogens are tested ( A. baumannii , K. pneumonia , and MRSA). Furthermore, the acute toxicity effects of Ag-NPs in zebrafish embryos (ZFE) ( Danio rerio ) are also examined in this study. The acute toxicity of Ag-NPs at different time points of post-fertilization (3, 12, 24, 48, 72, and 96 hours) eggs of zebrafish. Results shows dose-dependent antibacterial and antibiofilm activity, with significant inhibition observed at 100 and 200 μg/ml concentrations against A. baumannii, K. pneumonia , and MRSA. The lethal concentration (LC ₅₀ ) values determined as 12.5 and 50 μg/ml. The acute toxicity of Ag-NPs treated ZFE are displayed concentration-dependent mortality rates and increased hatching delay.