Hydrothermal synthesis, structural characterization, and biological evaluation of Fe-doped CuO nanosheets and their chitosan nanocomposite

• Fe-doped CuO nanostructures and chitosan composites exhibit tunable antibacterial efficacy and enhanced biocompatibility. • CF8O-Cs composites show selective and potent antibacterial activity against Gram-positive Staphylococcus aureus . • Chitosan functionalization reduces nanoparticle absorption by Gram-negative bacteria due to electrostatic repulsion. • Fe doping substantially decreases CuO cytotoxicity, resulting in improved safety for mammalian fibroblasts. In this study, Fe-doped copper oxide nanostructures (CF8O) and their chitosan-based composites (CF8O-Cs) were synthesized via a hydrothermal method and systematically characterized for biomedical applications. Comprehensive structural and morphological analyses (XRD, EDX, FESEM) established the formation of monoclinic-phase CuO nanosheets. Brunauer–Emmett–Teller (BET) analysis revealed that Fe doping significantly increases the surface area and pore volume of CuO, favoring greater nitrogen adsorption. Antibacterial activity was assessed against representative Gram-positive ( Staphylococcus aureus ) and Gram-negative ( Escherichia coli ) bacteria using viable cell counting. Pristine CF8O nanosheets exhibited potent, broad-spectrum bactericidal effects, while the chitosan-functionalized CF8O-Cs composite showed selective and enhanced activity against S. aureus but diminished efficacy against E. coli . Cytocompatibility, evaluated via MTT assay on L929 fibroblasts, demonstrated that Fe doping reduces the cytotoxicity of CuO nanoparticles compared to undoped counterparts. These results suggest that Fe-doped CuO and its chitosan composites offer tunable antibacterial performance and improved biocompatibility, supporting their promise for future biomedical and antimicrobial applications.