Si:WO3 sensors for noninvasive diabetes diagnosis by breath analysis

Here, pure and Si-doped WO₃ nanoparticle films are investigated as chemo-resistive acetone detectors. Flame spray pyrolysis was utilized to synthesize and directly deposit the sensitivite nanoparticles on sensor substrates with interdigitated Au electrodes. Doping with Si was used to thermally stabilize the acetone selective ε-WO₃ phase at the elevated operating temperatures of metal oxide gas sensors (300-500°C). The effect of static and dynamic testing conditions, such as operating temperature and gas flow-rate, were investigated. Finally, optimal detector operating temperatures are identified, and the feasibility of low acetone detection (ppb) in ideal (dry air) and realistic conditions (90% rh) by these simple Si-doped WO₃ detectors was demonstrated. The utilization of these portable solid state detectors has potential for noninvasive diabetes diagnosis by breath analysis.