Structural, mechanical and biomedical impacts of defects in Cu/Mg Co-doped ZnO nanoparticles

Zn_0.99-xCu_0.01Mg_xO (x = 0–0.05) nanoparticles were synthesized by a sol–gel route and examined to relate doping-induced lattice defects to biocompatibility for prospective biomedical use. X-ray diffraction confirmed single-phase wurtzite with no secondary phases, while Williamson–Hall models provided crystallite size and lattice microstrain/stress, separating strain from size effects. Photoluminescence (UV–visible) showed an Mg-dependent defect redistribution suppression of the green band (V_O) with concomitant changes in Zn_i, V_Zn, and O_i centers. SEM/EDS verified the expected composition and quasi-spherical agglomerated morphology. Hemolysis assays on human erythrocytes revealed a monotonic decrease in lysis with increasing Mg; samples with x ≥ 0.04 were non-hemolytic at 1.0 mg/mL (ISO <5 %). Overall, Mg-enabled defect passivation particularly V_O suppression correlates with improved blood compatibility, indicating that Cu/Mg co-doping is a practical lever to tailor ZnO nanoparticles for blood-contacting coatings, sensors, and implant interfaces.