ZnO nanowire florets promote the growth of human neurons

Abstract

Vertical nanowires, due to their 1-dimensional structure, chemical stability, biocompatibility and relative ease of manufacture are ideal candidates for biological interfaces in nanomedicine applications. The majority of live cell studies performed on vertical nanowires have mainly employed Si and GaP nanowires, whereas ZnO nanowires have been relatively unexplored. In this article, we demonstrate that the growth and adhesion of human NTera2.D1/hNT neurons can be modulated on ZnO nanowires. Vertical ZnO nanowires were fabricated using a time-controlled low temperature hydrothermal synthesis on pre-patterned seed regions that allows for precise control over nanowire morphology. We demonstrate that neuronal adhesion was enhanced when ZnO nanowires were below 500 nm long and at a density of 350 nanowires per µm2, increasing up to 33% compared to SiO2 surfaces. In contrast neuron adhesion was inhibited by longer and less dense nanowires. Furthermore, we demonstrate that neurons grew preferentially on individual florets of nanowires when the nanowires were fabricated into arrays of varying dimensions. Finally, we demonstrate that the neurons on individual nanowire florets were viable and displayed functional Ca2+ responses to glutamate stimulation that were comparable to neurons that were grown on SiO2.