Journal of Material Sciences & Engineering

Shape and size effect of doped ZnO nanoparticles on their antimicrobial efficacy

Abstract

Yongling Wu

Silver ion and silver nanoparticles are well known for their ability to kill bacteria effectively. However, the side effect of high dose silver on humans especially children has been a major concern when designing antimicrobial coatings for daily life environment.  ZnO quantum dots have been studied intensively by doping with different levels of elements, which emit the constituents of white light covering violet, blue, green, yellow, and red, making it very attractive for the application as luminescent material and bio-markers. ZnO nanorod arrays were used to fabricate LED light and highly sensitive chemical sensors for O2 and NO2 and hydrazine (N2H4) [5] respectively. The most important property of ZnO is its antimicrobial property and photocatalytic activity under UV-light owning to the disruption of cell membrane during the nanoparticle’s interaction with the bacterial. In this paper, we report a study into the effect of size, shape and metal ions doping of ZnO nanoparticles on the bacterial killing efficacy. We use a solution synthesis method varying the way of adding precursors, the doping element type and amount, the surface capping agents, and the processing parameters. We obtained several shapes (spherical, hexagonal prism, nanorod, flower-like etc.) in different sizes ranging from 30nm to 100nm. We analyzed the morphological structures of the particles, measured the antibacterial properties using JIS Z2801 method, and finally confirmed that the combined effect of size, doping, shape and surface morphology contributed to the antibacterial property of ZnO nanoparticles. Our research suggests that only 0.05-0.2% of silver doping into ZnO could effectively reduce the size of ZnO nanoparticles with Ag ions preferentially located on surface of particles making high efficacy of antibacterial property.