Functionalized ZnO nanoparticles with tannic acid as an antibacterial agent against Methicillin-Resistant Staphylococcus Aureus

The significant increase in the use of antibiotics in medicine and agriculture has led to the production of antibiotic-resistant bacteria. According to the WHO, antibiotic resistance is a major global threat [۱][۲]. Staphylococcus aureus (S. aureus), especially the methicillin-resistant Staphylococcus aureus (MRSA), is an important challenge in medicine and hospital infection control. Among the new approaches to combat antibiotic resistance, zinc oxide nanoparticles (ZnONPs) is considered very important due to their high chemical stability, photocatalytic efficiency, biocompatibility, and antibacterial properties [۳][۴]. Tannic acid (TA), a plant polyphenol-rich in hydroxyl groups, can interact with proteins, polysaccharides, and metal ions, and has antioxidant and antibacterial activity [۵][۶]. The purpose of this study was to investigate the antibacterial activity of ZnONPs coated with tannic acid (ZnO@TA) on standard S. aureus and MRSA strains. For this purpose, ZnO@TANPs were synthesized and characterized by FT-IR, DLS, XRD, and zeta potential. ZnO@TANPs exhibited higher antioxidant activity as compared to ZnONPs by DPPH assay. The MIC value of ZnONPs and ZnO@TANPs against standard S. aureus was equal to ۲۵۰ μg/mL. The MIC value of ZnO@TANPs for MSRA bacteria was four times lower than that of ZnONPs. MBC values for both strains were more than ۱۰۰۰ μg/mL. Both NPs at MIC could inhibit biofilm formation by the tested strains, whereas ZnO@TANPs at concentrations of ۱.۲ x MIC and ۱.۴ x MIC showed lower antibiofilm activity than that of ZnONPs. In summary, ZnO@TANPs seem to have more antibacterial activity than ZnONPs against MRSA bacteria, which is probably due to their antioxidant activity.

کلیدواژه ها:

Zinc oxide nanoparticles ، Tannic acid ، Antibacterial activity ، Antioxidant ، Methicillin-resistant staphylococcus aureus (MRSA).