Investigating the antioxidant and antibacterial properties of ZnO nanoparticles coated with chondroitin sulfate against Staphylococcus Aureus

Staphylococcus aureus (S. aureus) is considered as common pathogenic bacteria with antibiotic resistance properties [۱-۳]. Currently, nanomedicines have been suggested to deal with antibiotic resistance [۴, ۵]. Zinc oxide nanoparticles (ZnO-NPs) have chemical and thermal stability, high biocompatibility, antioxidant, and antibacterial activity [۶]. Coating surface of ZnO-NPs with different biomolecules have been proposed to improve their cytotoxic activity [۷, ۸]. In this study, the antioxidant property of ZnO-NPs coated with chondroitin sulfate (CS) mediated by cysteine (ZnO@Cys@CS) and their antibacterial activity on standard S. aureus and clinical methicillin-resistant S. aureus (MRSA) strains were investigated. For this purpose, the surface of synthesized ZnO-NPs by thermal solvent method was coated with cysteine (Cys) and CS. ZnO@Cys@CS-NPs were characterized by XRD, FT-IR, zeta potential, and DLS. Antibacterial activity of ZnO-NPs and ZnO@Cys@CS-NPs against the standard strain showed MIC values of ۲۵۰ and ۵۰۰ μg/mL, respectively. The MIC value for both nanoparticles against the MRSA strain was the same and equal to ۲۵۰ μg/mL. The MBC of both nanoparticles for the tested strains was determined to be more than ۱۰۰۰ μg/mL. The results of DPPH and superoxide free radical inhibition assays showed higher antioxidant property of ZnO@Cys@CS-NPs than ZnO-NPs. Both nanoparticles at MIC were able to inhibit biofilm formation by both strains, While, ZnO@Cys@CS-NPs at ۱/۲ x MIC and ۱/۴ x MIC concentrations showed more antibiofilm activity by the standard strain as compared to MRSA. In conclusion, surface modification of ZnO-NPs by CS-coating seem to increase its antioxidant activity without improving its antibacterial activity against both standard and MRSA bacteria.

کلیدواژه ها:

Staphylococcus aureus ، ZnO nanoparticles ، chondroitin sulfate ، antioxidant activity ، antibacterial activity.