Porous PDMS–ZnO\nWearable Gas Sensor for Acetone\nBiomarker Detection and Breath Analysis

In response to the growing demand for global health monitoring,\nwe report a nonintrusive health detection method using a compact,\nconformal wearable ultraviolet (UV)-assisted gas-sensing system based\non an intrinsically flexible porous polydimethylsiloxane (PDMS)-zinc\noxide (ZnO) composite layer (PPZL) for the breath acetone (BrAce)\ndetection and breath event analysis. The enhanced acetone response\nis attributed to the synergistic effect of UV irradiation and the\nhigh surface area of the porous structure, which also improves the\nmechanical robustness. The UV-assisted wearable sensor reliably detects\nacetone concentrations ranging from 1 to 100 ppm at room temperature\nunder 4.05 mW/cm<sup>2</sup> UV intensity, even under mechanical strains\nsuch as a bending radius of 5 mm and 60% tensile strain. It accurately\nanalyzes different breathing patterns (12–20 breaths per minute)\nand BrAce concentrations, maintaining a stable performance over 20\ndays with less than 5% signal degradation. The sensor exhibits response\nand recovery times of average 110–150 and 130–180 s,\nrespectively, and maintains a consistent 3 ppm BrAce response under\nvarying humidity levels up to 70% relative humidity, ensuring accurate\ndetection of BrAce concentrations during real-world breath tests.\nAdditionally, the sensor targets only specific gases, and the sensor’s\nselectivity is not a key concern. This flexible acetone gas sensor\noffers a portable solution for health management and a fabrication\nmethod for designing flexible metal oxide materials.