Project Summary/Abstract Measuring alcohol consumption is important to individual health and the prevention of adverse consequences of drinking. There are tremendous needs for wearable alcohol continuous sensing devices that are accurate, minimal- or non-invasive, unobstructive and affordable. However, existing technologies cannot provide alcohol sensors with all specifications desired by wearable devices, including size, power, sensitivity, specificity, safety, manufacturability and cost. The proposed project is to develop an alcohol sensor suitable for wearable applications by innovating electrochemical alcohol sensors. The innovation uses microfabrication techniques to achieve high sensitivity, high safety, good manufacturability and low cost with a miniaturized membraneless structure. The catalytic effect of the designed electrolyte-electrode interface achieves high sensitivity and high selectivity. The size of the sensor is less than 2x2 millimeters, can unlock many possibilities for wearable, smartphone, and automobile for alcohol detection in breath, interstitial fluid, or blood. In this project, we aim to demonstrate the technology by an examplary ring form factor wireless powered wearable device that can accurately and continuously monitor the alcohol level in body fluid. In Phase I, in addition to the alcohol sensor, a minimal invasive biocompatible microneedle array is designed to painlessly sample and deliver the interstitial fluid to the sensor. The microneedle array is designed to be processed along with the sensor on the same silicon substrate. The entire process is compatible with the fabrication of complimentary oxde metal semiconductor (CMOS), allowing the further monolithic integration of the microneedle array, the alcohol sensor, and the CMOS sensor readout integrated circuit (IC) in Phase II.