Investigation of photocatalytic degradation of methylene blue and antibacterial activity performance against S. aureus and E. coli by copper oxide nanocomposites coated with chitosan biopolymer facilitated by Aegle marmelos

The increasing interest in synthesizing nanocomposites using environmentally friendly methods has drawn considerable attention due to their non-toxic nature, cost-effectiveness, and ease of production. This research investigates the synthesis of copper oxide nanoparticles and nanocomposites using an aqueous leaf extract of Aegle marmelos, along with chitosan biomolecules to improve their biological properties. The physicochemical analysis of copper oxide nanoparticles and chitosan-embedded copper oxide nanocomposites employed several techniques including UV-Visible spectroscopy, Fourier transform infrared spectroscopy, X-ray Diffraction, High-Resolution Transmission Electron Microscopy and Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The antibacterial efficacy of the copper oxide nanoparticles and nanocomposites was assessed against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Additionally, the bio-functionalized copper oxide nanoparticles and nanocomposites exhibited photocatalytic capabilities in degrading the industrial dye Methylene Blue. The synthesized nanostructures showed favorable sizes of 13.7 nm for copper oxide nanoparticles and 25.8 nm for nanocomposites, both displaying a crystalline structure. Notably, the maximum zone of inhibition is obtained for copper oxide nanocomposites against Staphylococcus aureus (30 mm) and Escherichia coli (25 mm) while for copper oxide nanoparticles, the inhibition zones were recorded as 21 mm for Staphylococcus aureus and 15 mm for Escherichia coli. Moreover, the copper oxide nanoparticles and nanocomposites displayed efficient photocatalytic dye degradation against Methylene Blue, achieving degradation rates of up to 60% and 92%, respectively, within 70 min without the use of any reducing agent. Bio-functionalized copper oxide nanocomposites show promising potential for biomedical applications and industrial wastewater treatment.