Spatio-Design of Multidimensional Prickly Zn-Doped CuO Nanoparticle for Efficient Bacterial Killing

Zinc-doped copper oxide (Zn-CuO) is a promising material for the development of antimicrobial materials due to its safety and the highly effective antibacterial activities against multidrug-resistant bacteria. As known, the intracellular reactive oxygen species produced by Zn-CuO nanomaterials play important role in bacterial killing; however, the relationship between their nanostructure and antibacterial activity has yet to be elucidated. In this study, we prepare, for the first time, Zn-CuO nanoparticles with prickly nanostructures via a green sonochemical method. The resultant prickly Zn-CuO nanoparticles exhibit strong antibacterial activity that can kill 99.0% of bacteria within 10 min under dark conditions and significantly hamper bacterial growth in Luria-Bertani culture medium. It is also found that prickly Zn-CuO nanoparticles show a nanopiercing process on bacterial membrane and subsequently lead to accelerated cytoplasma leakage. To further check the effect of nanopiercing on membrane damage and bacterial killing, Zn-CuO nanorods are employed with two sharp tips for comparison. Due to the great change of nanopiercing process from multidimension (prickly) to 1D (rod-like), the Zn-CuO nanorods exhibit distinctly lower antibacterial activity compared with prickly Zn-CuO nanoparticles. This finding definitely indicates the importance of nanostructures on the antibacterial activity of Zn-CuO nanoparticles, i.e., architecture-enhanced nanopiercing for bacterial killing.