Facile approach to enhance the antibacterial activity of ZnO nanoparticles

ABSTRACT

In this study, we carried out a simple surface modification of zinc oxide nanoparticles (ZnO NPs) using didodecyldimethylammonium bromide (DDAB) as a cationic surfactant. The crystallographic properties, optical absorption, and morphology of the ZnO NPs did not change after the surface modification. The FT-IR spectra of the surface-modified ZnO NPs (SM-ZnO) showed the characteristic peaks of DDAB, which shifted to higher frequencies with an increase in the DDAB content. The zeta potential of the SM-ZnO NPs increased with an increase in the DDAB content and reaction time. The sedimentation test results revealed that the SM-ZnO NPs exhibited better dispersion and lower aggregation than pure ZnO NPs. The SM-ZnO NPs showed high surface positive charge, thereby generating additional Zn²⁺ with higher surface tendency to the bacteria. The SM-ZnO NPs showed improved antibacterial activity against both Staphylococcus aureus and Escherichia coli strains as compared to the pure ZnO NPs.

KEYWORDS:

• Surface modification
• cationic surfactant
• positive charge
• dispersion
• antibacterial activity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Research Foundation of Korea (NRF) and the Korean government (MSIP) [grant number 2020R1A2B5B01001797].