Cytotoxicity of ZnO Nanowire Arrays on Excitable Cells

Abstract

Zinc oxide (ZnO) nanowires have been widely studied for their applications in electronics, optics, and catalysts. Their semiconducting, piezoelectric, fluorescent, and antibacterial properties have also attracted broad interest in their biomedical applications. Thus, it is imperative to evaluate the biosafety of ZnO nanowires and their biological effects. In this study, the cellular level biological effects of ZnO nanowire arrays are specifically tested on three types of excitable cells, including NG108-15 neuronal cell line, HL-1 cardiac muscle cell line, and neonatal rat cardiomyocytes. Vertically aligned and densely packed ZnO nanowire arrays are synthesized using a solution-based method and used as a substrate for cell culture. The metabolism levels of all three types of cells cultured on ZnO nanowire arrays are studied using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays of a full factorial design. Under the studied settings, the results show statistically significant inhibitory effects of ZnO nanowire arrays on the metabolism of NG108-15 and HL-1 cells in comparison to gold, glass, and polystyrene substrates, and on the metabolism of cardiomyocytes in comparison to gold substrate.

Zinc oxide nanorod array as an inhibitory biointerface

“…When interacting with cells, 1D ZnO nanostructure arrays showed either biocompatibility [7][8][9][10][11][12] or induced inhibitory effects. [8,9,[12][13][14][15] The different biological effects can be due to the different surface morphologies (diameters, spacings, lengths, densities, shapes, and alignments) and cell types in different studies. Thus, the biological effects of 1D ZnO nanostructure arrays need to be studied case by case.…”

“…[9,13] Interestingly, when interacting with 1D ZnO nanostructure arrays, fast-dividing cell lines with inhibited adhesion eventually died, [12,13,15] whereas primary cells with inhibited adhesion remained viable. [12,16] The cause to cell death underneath ZnO NRAs (with or without Au-coating) should also be physical. Au-coated cover glasses were probably spaced by a thin solution layer from the cells, which explains the survival of the underneath cells.…”

“…Cells showed good adhesion, proliferation, differentiation, and viability when interacting with 1D ZnO nanostructure arrays. [7][8][9][10][11][12] However, 1D ZnO nanostructure arrays also induced inhibitory effects on cells, decreasing cell adhesion and viability and inhibiting differentiation. [8,9,[12][13][14][15] Thus, it is critical to fully understand the mechanism so that we can modulate cellular responses in a controlled manner.…”

“…Second, it depends on cell type. For example, cell lines respond differently than primary cells, [4,12,16] and different cell lines respond differently as well. [8,15] Additionally, if ZnO's surface chemistry leads to production of reactive oxygen species [17] and/or Zn 2+ dissolution, [14] if cells sense piezoelectricity, [10] and if 1D ZnO nanostructure arrays interact with cells as a substrate or patch, could all affect the biological effects.…”

Effective Neural Photostimulation Using Indium-Based Type-II Quantum Dots

“…46−48 Advantageously, it has high radiation, chemical, and thermal resistance; 46 in addition, it shows higher biocompatibility compared to nonoxide materials and has been used for various biological applications. 49,50 Moreover, it can provide an oxidation-resistant protective and electron-transporting layer on the InP core. Previously, we demonstrated efficient luminescent solar concentrators (LSCs) based on these type-II QDs.…”