Broad spectrum antibiofilm and antibacterial potency of green-synthesized CaCO₃ nanoparticles using parsley extract: Enhanced physicochemical characteristics

Abstract

Abstract Calcium carbonate (CaCO₃) nanoparticles mediated by Petroselinum crispum (parsley) followed by comparison with commercial CaCO₃ nanoparticles. UV-Vis and FTIR analyses confirmed the presence of phytochemicals containing hydroxyl, carbonyl, and aliphatic functional groups, which acted as reducing, capping, and stabilizing agents. XRD confirmed predominantly calcite in both samples, with mean crystallite sizes of 51.97 nm and 60.90 nm for commercial and green-synthesised nanoparticles, respectively, while TEM showed mean particle diameters of 66.11 nm and 76.45 nm. SEM revealed morphological differences caused by phytochemical surface functionalization. Green-synthesised CaCO₃ nanoparticles showed a greater colloidal stability (-26.05 mV vs. -18.25 mV), whereas commercial nanoparticles had a higher specific surface area (17.926 m²/g vs. 15.61 m²/g) due to their smaller size. Antibacterial testing against Streptococcus mutans and Staphylococcus aureus showed that green-synthesised nanoparticles had a fourfold lower Minimum Inhibitory Concentration (MIC) against S. mutans (125 µg/mL vs. 500 µg/mL) and larger inhibition zones at all tested concentrations, suggesting enhanced synergistic bactericidal activity. In contrast, commercial nanoparticles showed stronger concentration-independent antibiofilm activity, likely due to their smaller size and higher surface area, which promoted penetration of the extracellular polymeric matrix. These complementary effects indicate that P. crispum-mediated green synthesis can produce biofunctional CaCO₃ nanoparticles with improved antibacterial potential against clinically important oral pathogens, supporting their use in dental caries prevention and broader biomedical applications.