Cobalt oxide-chitosan based nanocomposites: Synthesis, characterization and their potential pharmaceutical applications.

This research aimed to prepare, characterize, and investigate the biological efficacy of chitosan‑cobalt (II) oxide hybrid nanocomposites against a variety of micrograms. Analytical methods, FTIR, SEM, XRD, and EDX, were utilized to thoroughly characterize the produced CS-CoO nanocomposite. In FTIR spectra, the presence of the chitosan peaks in addition to that of CoO at 681 and 558 cm-1 confirmed that CoO molecules interact with the chitosan backbone. Moreover, in the XRD measurements, significantly less chitosan crystallinity was observed. Due to the incorporation of a larger amount of cobalt oxide within the polymer matrix. Applying the Debye-Sherrer calculation, the crystallite size was obviously reduced from 48.24 nm (5 wt %) to 19.27 nm (20 wt %) for the obtained nanocomposites. Furthermore, SEM measurements showed a transformation in the chitosan surface with the physical adsorption of CoO molecules on the surface active sites of chitosan that were visible in SEM graphs. Additionally, EDX determined the amount of Co element within the chitosan, with the sample of 20 wt % weight being found to be 19.26 wt %. The variable dose well-diffusion method was utilized to assess the efficacy of the CS-Co nanocomposite against a wide range of bacteria and fungi. CS - CoO nanocomposite is more effective than chitosan alone as an antibacterial agent against both Gram-positive and Gram-negative bacteria. Moreover, the MTT approach was employed to measure the cytotoxicity based on the cell viability of different cancer cell lines under different UV expositions. The proportion of the destroyed cells elevated due to the easy diffusion of CS - CoO nanocomposite into cancer cells as UV-free anticancer activity. UV exposition has stimulated the anticancer activity, which was attributed to an increase in ROS generation caused by the increased dose of the chitosan and its CS - CoO nanocomposites. Furthermore, the antioxidant capacities of the prepared nano-composites thin films were validated using the DPPH free radical scavenging method and showed good antioxidant activities with the DPPH radical compared with standard vitamin C. It has been noticed that by increasing the content of CoO nanoparticles from 5 to 20 wt %, the biological activity of the prepared nanocomposites was enhanced.