Effect and Properties of Surface-Modified Copper Doped ZnO Nanoparticles (Cu:ZnO NPs) on Killing Curves of Bacterial Pathogens.

Background: The current study aimed to determine the effect and properties of surface-modified copper doped Cu:ZnO NPs on killing curves of bacterial pathogens. Methods: Preparation of in situ surface-modified copper doped ZnO nanoparticles (Cu:ZnO NPs) was done according to standard procedure. Assay for antimicrobial activity of Cu:ZnO NPs against bacterial pathogens was carried out based on disc diffusion method. Determination of shelf life, thermal and pH stability of antibacterial activity of Cu:ZnO NPs was done and residual activity was determined against the target cultures. Results: FTIR spectra indicate that the nanomaterials synthesized have higher peak intensity compared with reagent grade ZnO. According to the SEM image the nanoparticles synthesized have different size and heterogeneous morphology. 400 ppm of Cu:ZnO NPs gave zones of inhibition with diameters of 9.0 - 16 mm against the target cultures. Amongst the target cultures, Escherchia coli was the most sensitive to the Cu:ZnO NPs inhibition zone diameter 16 mm; whereas, 9 mm wide inhibition zone was obtained against Staphylococcus aureus. The Cu:ZnO NPs was fairly stable for a period of 60 days at room temperature (RT) showing lost of only 20% and 30% antibacterial activity as tested against E. coli and S. aureus, respectively. The Cu:ZnO NPs was quite stable at this pH and temperature range tested against both E. coli and S. aureus. Conclusion: Surface-modified copper doped Cu:ZnO NPs have significant potential for their usefulness as antibacterial agents. [ABSTRACT FROM AUTHOR]