Construction of flexible and wearable 3D TiO2 NTs@Ti mesh for physiological detection based on sweat

Abstract

The biosensors with flexibility and breathability turn out to be a vital means of non-intrusive detection of multi-components biochemical markers in human sweat. For this end, three-dimensional (3D) structure TiO 2 nanotube arrays were in-situ established on Ti mesh by using the anodizing method in the present study. The 3D structure TiO 2 nanotube arrays@Ti mesh (3D TiO₂ NTs@Ti mesh) exhibited an anatase structure and a nanotube with pore size of 60–80 ​nm. 3D TiO₂ NTs@Ti mesh with good corrosion resistance made it possible to be a sweat sensor since the tube is capable of penetrating deeper into the pores to absorb more sweat, while mesh substrate exhibits high gas permeability to avoid skin damage. Sweat sensing performance was tested by using cyclic voltammetry (CV) curve, and the response current intensity increased with the increase in the concentrations of Na + , K + , urea and lactic acid while the current intensity decreases as the glucose concentration increases in the electrolyte solution. The semi-quantitative analysis was conducted to discriminate sweat component from each other, thereby revealing an effective recognition capability of the 3D TiO₂ NTs@Ti mesh. The density of the states (DOS) for anatase TiO₂ (101) nanotube that adsorbed different components were calculated. As suggested from the results, the adsorbed sweat components narrowed the band gap of anatase TiO 2 , thereby improving the current intensity.