Noninvasive breath acetone sensors, in particular metal oxide based chemo-resistive sensors, have been actively researched recently for daily diabetes diagnosis. To find a safer alternative to the flame spray pyrolysis processing method, screen printing of commercial TiO2 paste is employed in the fabrication of metal oxide semiconductor chemo-resistors, without involving open flame, high temperature and costly instruments. The TiO2 sensing layer is found to have a desirable porous structure, with a specific surface area of 72.7 m2 g−1, when investigated using scanning electron microscopy and the Brunauer–Emmett–Teller isotherm. The new sensors are able to detect 1.5 ppm acetone, and are sensitive enough for type I diabetes diagnosis. The sensitivity survives in the presence of 90% relative humidity, offering a long targeted selectivity yet to be achieved, but essential for human breath analysis.
