Find in Library

Chitosan-copper oxide (CHT-CuO) nanocomposite was synthesized using olive leaf extract (OLE) as reducing agent and CuSO₄⋅5H₂O as precursor. CHT-CuO nanocomposite was prepared using an in situ method in which OLE was added to a solution of chitosan and CuSO₄⋅5H₂O mixture in the ratio of 1:5 (<i>v</i>/<i>v</i>) and heated at a temperature of 90 °C. The obtained CHT-CuO nanocomposite was characterized using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectrophotometry, energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FTIR), and high-resolution transmission electron microscopy (TEM). TEM results indicated that CHT-CuO nanocomposite are spherical in shape with size ranging from 3.5 to 6.0 nm. Antibacterial activity of the synthesized nanocomposites was evaluated against Gram-positive (<i>Bacillus cereus</i>, <i>Staphyloccous haemolytica</i> and <i>Micrococcus Luteus</i>) and Gram-negative (<i>Escherichia coli</i>, <i>Pseudomonas citronellolis</i>, <i>Pseudomonas aeruginosa</i>, <i>kliebisella</i> sp., <i>Bradyrhizobium japonicum</i> and <i>Ralstonia pickettii</i>) species by cup platting or disc diffusion method. Overall, against all tested bacterial strains, the diameters of the inhibition zone of the three nanocomposites fell between 6 and 24 mm, and the order of the antimicrobial activity was as follows: CuO-1.0 > CuO-0.5 > CuO-2.0. The reference antibiotic amoxicillin and ciprofloxacin showed greater activity based on the diameter of zones of inhibition (between 15–32 mm) except for <i>S. heamolytica</i> and <i>P. citronellolis</i> bacteria strains. The nanocomposites MIC/MBC were between 0.1 and 0.01% against all tested bacteria, except <i>S. heamolityca</i> (>0.1%). Based on MIC/MBC values, CuO-0.5 and CuO-1.0 were more active than CuO-2.0, in line with the observations from the disc diffusion experiment. The findings indicate that these nanocomposites are efficacious against bacteria; however, Gram-positive bacteria were less susceptible. The synthesized CHT-CuO nanocomposite shows promising antimicrobial activities and could be utilized as an antibacterial agent in packaging and medical applications.