Oral infections caused by antibiotic-resistant bacteria represent an emerging biomedical hazard and growing challenge for modern dentistry. To address this issue, Ag– and Cu–ZnO nanocomposites (NCs) were synthesized using ZnO carrier to combat the oral pathogens Streptococcus mutans and Streptococcus sobrinus. A comprehensive analysis of chemically synthesized metal oxide nanocomposites (MONCs) was performed, combining physicochemical characterization (TEM, XRD, ζ-potential, DLS, pH, and PFO/PSO kinetic models) with biological toxicity assessment (MIC, ATR–FTIR, SEM, and FAMEs) to better understand their antimicrobial mechanisms. The results confirmed that the synthesized nanoproducts fulfill the criteria for nanomaterials (NMs) (particle size < 100 nm). Among them, Ag–ZnO exhibited the highest antibacterial activity against both strains (MIC = 50 mg L−1). Kinetic modeling revealed faster and more efficient Ag ion release from Ag–ZnO NCs compared to Cu from Cu–ZnO NCs. Molecular analyses indicated strong MONC–bacterial interactions at the cell surface, leading to changes in protein secondary structures, alterations in lipid composition, and disruption of Gram-positive bacterial membranes. Additionally, Ag–ZnO inhibited chain and cluster formation in both bacterial species, while Cu–ZnO affected only S. sobrinus. Overall, Ag– and Cu–ZnO NCs show strong potential as antimicrobial agents against oral pathogens.
AHMED et al. (Sun,) studied this question.