AuNPs-amoxicillin nanocarriers enhance antibacterial activity against methicillin-resistant Staphylococcus aureus: Efficacy and toxicity evaluation.

INTRODUCTION The increasing prevalence of antibiotic-resistant bacteria, particularly Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA), necessitates the development of more effective antibacterial strategies. Gold nanoparticles (AuNPs) have emerged as promising nanocarriers to improve antibiotic delivery and antibacterial efficacy.

Methods

Amox-AuNPs were synthesized using the Turkevich method and characterized by UV-Vis spectroscopy, FTIR, particle size analysis, zeta potential, FE-SEM, TEM, and stability evaluation. Antibacterial activity was assessed using microdilution and disk diffusion assays. Cytocompatibility and safety were evaluated using the MTT assay on MCF-10A cells and the Fish Embryo Toxicity (FET) test. The selectivity index (SI) was determined from the estimated IC50 and MIC90 values.

Results

Characterization confirmed successful conjugation of amoxicillin onto AuNPs with high entrapment efficiency (76.89%) and good colloidal stability over 20 days. Amox-AuNPs exhibited significantly enhanced antibacterial activity against S. aureus and MRSA, with an estimated MIC90 of 2.38 ppm against MRSA. Cytotoxicity testing demonstrated cell viability above 70%, while the estimated SI of 14.78 and FET results indicated favorable biocompatibility and safety.

Conclusion

Amox-AuNPs effectively enhanced the antibacterial activity of amoxicillin while maintaining good physicochemical stability, favorable biocompatibility, and a wide therapeutic window, highlighting their potential as a nanocarrier for combating antibiotic-resistant bacteria.