فهرست نشریات علمی دسترسی آزاد ایران

Predominantly calcite-phase CaO nanoparticles were prepared by alka-line precipitation followed by calcination and characterized by SEM, XRD, FTIR, UV–Vis, and bioassays. XRD confirmed nanocrystallinity with crystallite sizes of approximately 37–45 nm and reflections indi-cating substantial conversion of CaO to calcite during processing. FTIR showed surface hydroxyls and carbonate groups consistent with hydrat-ed/carbonated CaO, and UV–Vis revealed strong absorption below 400 nm. Antibacterial activity was dose-dependent, with the largest inhibi-tion zone (24 mm) against Escherichia coli at 1,500 μg mL⁻¹. Hemocom-patibility assays showed increasing hemolysis with dose (12.4% at 250 μg mL⁻¹ and 21.0% at 750 μg mL⁻¹) exceeding the conventional 10% safety threshold, while brine shrimp assays indicated low acute aquatic toxicity (LC₅₀ > 1,000 μg mL⁻¹; 33.3% mortality at that dose). Overall, these calcite-rich CaO nanoparticles exhibit notable antimicrobial ef-fects but pose hemolysis risks at higher concentrations; safer deploy-ment may benefit from immobilized or buffered formats and tighter CO₂ control during synthesis to preserve phase stability.