Nanowire Array Breath Acetone Sensor for Diabetes Monitoring

Abstract Diabetic ketoacidosis (DKA) is a life‐threatening acute complication of diabetes characterized by the accumulation of ketone bodies in the blood. Breath acetone, a ketone, directly correlates with blood ketones. Therefore, monitoring breath acetone can significantly enhance the safety and efficacy of diabetes care. In this work, the design and fabrication of an InP/Pt/chitosan nanowire array‐based chemiresistive acetone sensor is reported. By incorporation of chitosan as a surface‐functional layer and a Pt Schottky contact for efficient charge transfer processes and photovoltaic effect, self‐powered, highly selective acetone sensing is achieved. The sensor has exhibited an ultra‐wide acetone detection range from sub‐ppb to >100 000 ppm level at room temperature, covering those in the exhaled breath from healthy individuals (300–800 ppb) to people at high risk of DKA (>75 ppm). The nanowire sensor has also been successfully integrated into a handheld breath testing prototype, the Ketowhistle, which can successfully detect different ranges of acetone concentrations in simulated breath samples. The Ketowhistle demonstrates the immediate potential for non‐invasive ketone monitoring for people living with diabetes, in particular for DKA prevention.