In this paper we demonstrate a wearable tattoo-based alcohol biosensing system for noninvasive alcohol monitoring in induced sweat. The skin-worn alcohol monitoring platform integrates an iontophoretic-biosensing temporary tattoo system along with flexible wireless electronics. The wearable prototype enables the transdermal delivery of the pilocarpine drug to induce sweat via iontophoresis and amperometric detection of ethanol in the generated sweat using the alcohol-oxidase enzyme and the Prussian Blue electrode transducer. The new skin-compliant biosensor displays a highly selective and sensitive response to ethanol. On-body results with human subjects show distinct differences in the current response before and after alcohol consumption, reflecting the increase of ethanol levels. The skin-worn alcohol sensor is coupled with a flexible electronics board, which controls the iontophoresis/amperometry operation and transmits data wirelessly in real time via Bluetooth communication. The new wireless epidermal iontophoretic-biosensing system offers considerable promise for noninvasive monitoring of alcohol consumption in practical settings and can be readily expanded toward the monitoring of additional analytes. 

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