Gold Nanowire Aerogel-Based Biosensor for Highly Sensitive Ethanol Detection in Simulated Sweat

The devices with non-invasive characteristics have aroused people’s wide concern based on sweat analysis, such as providing real-time and accurate test of ethanol concentration. Unfortunately, these devices show limited selectivity, sensitivity, and stability owing to the existing planar electrodes with sluggish mass transport and inefficient active site utilization. The Au NW-gel bioelectrode exhibited good and quick linear current responses toward a broad range of ethanol concentration from 0.01 to 0.5 M. It was validated to an appreciable stability and selectivity to ethanol detection in the existences of sodium chloride, lactic acid, and urea. The abnormal concentration of ethanol in human’s biofluids is the index of unhealthy conditions from internal diseases. Herein, we introduce the application of gold nanowire aerogel (Au NW-gel) in detecting the concentration of ethanol in simulated human sweat. A preparation method based on substrate-assisted growth method is introduced. The length of Au NW synthesized by the substrate-assisted growth method is 10–20 μm. Au NW-gel has an ultralow density and high gold content, which can reduce the internal resistance of the electrode sufficiently. The pore structure of aerogel can accelerate the mass transfer process and make the Au NW-gel have excellent performance. The linear relationship between peak current and ethanol concentration in simulated sweat is established, and the retention capability of the biosensor is more than 83%. Furthermore, a simulation model is developed to validate the robust mass transfer and electrochemical performance of the porous electrode. The Au NW-gel-based electrode provides an effective pathway for detecting the ethanol content in sweat precisely.