Seaweed-Mediated Synthesis of Copper Oxide Nanoparticles and Evaluation of Their Antibacterial and Antibiofilm Activity Against Fish Pathogens

Bacterial diseases are one of the major causative factors for fish mortality and economic losses in aquaculture sector. Most of the pathogenic bacteria exists in biofilms, which offer protection from antibiotics and other infection control measures. In the present study, the antibacterial and antibiofilm activities of green synthesized copper oxide nanoparticles were tested against selected fish pathogens. Copper oxide nanoparticles (CuO-NPs) were synthesized using brown seaweed, Sargassum vulgare, extract. The biosynthesized NPs were characterized using UV-visible spectroscopy analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) analysis, an energy dispersive X-ray analyzer (EDX) and X-ray diffraction (XRD). The SEM examination of morphology revealed predominantly spherical particles with some degrees of aggregation in CuO-NPs. The polycrystalline nature of CuO-NPs was confirmed in the XRD analysis. Furthermore, CuO-NPs exhibited antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH). The prepared NPs also demonstrated antibacterial and biofilm formation inhibition activities against fish pathogens with a maximum biofilm inhibition of 95% against Vibrio anguillarum. Overall, the findings suggest that the S. vulgare mediated CuO-NPs have potential for further investigation in fish disease control in aquaculture due to their antibacterial and biofilm inhibition effects against fish pathogens.