Metal-Oxide-Decorated Mesoporous Silica Chemiresistors for Exhaled Biomarker Detection.

A metal-oxide-decorated mesoporous silica (MOMS) chemiresistor platform enables the selective detection of disease-specific volatile organic compounds (VOCs) in exhaled breath. Functionalization of these mesoporous structures with metals and metal oxides facilitates the detection of a wide range of VOCs. To create a sensing architecture with a bicontinuous morphology that optimizes molecular diffusion and electron transport pathways, we employ physically confined polymerization-induced phase separation (PC-PIPS) to fabricate template-directed mesoporous structures with controlled film thicknesses ranging from 1 to 5 μm. Incorporation of metal oxides (SnO2, ZnO) and noble metals (Pt, Au) forms p-n heterojunctions, enhancing sensitivity and selectivity through modulation of electron depletion layers. The MOMS chemiresistors demonstrate distinct response patterns toward key biomarkers, including hydrogen sulfide (periodontal disease), toluene (gingivitis), formaldehyde (oral carcinoma), and acetone (diabetes mellitus). Response magnitudes range from 1.75-5.66 at 10 ppm to 5.56-12.13 at 100 ppm of H2S, with unique electronic signatures, enabling identification of complex gas mixtures. This scalable and versatile fabrication approach establishes MOMS chemiresistors as a promising platform for noninvasive, early-stage disease detection via breath analysis.