Controlled Synthesis and Biocompatibility of Water-Soluble ZnO Nanorods/Au Nanocomposites with Tunable UV and Visible Emission Intensity

Abstract

ZnO nanorods/Au nanocomposites with Au nanocrystals growing at tips of ZnO nanorods or located along the surface of the nanorods can be synthesized via a facile low-cost solution method. The number of Au nanoparticles grown on ZnO nanorods can be controlled by tuning the molar ratio of ZnO to HAuCl 4; thus, the ZnO/Au heterostructures displayed tunable UV and visible emission intensity. The cytotoxic studies on two different cell lines (CHO cells and Hela cells) indicated that ZnO/Au hybrid nanocrystals are biologically nontoxic. The MTT assays of these two cells are consistent, showing that ZnO/Au hybrid nanomaterials were low cytotoxic at concentrations of 10 μg/mL. It is found that cytotoxicity of ZnO/Au hybrid nanocomposites mainly comes from ZnO nanorods. Cellular uptake experiments revealed the ZnO/Au hybrid nanocrystals can enter into the endosomes and the cytosol. The as-prepared ZnO/Au hybrid nanocomposites with good biocompatibility may have potential applications in biomedicine.