Selective Diagnosis of Diabetes Using Pt-Functionalized WO₃ Hemitube Networks As a Sensing Layer of Acetone in Exhaled Breath

Thin-walled WO₃ hemitubes and catalytic Pt-functionalized WO₃ hemitubes were synthesized via a polymeric fiber-templating route and used as exhaled breath sensing layers for potential diagnosis of halitosis and diabetes through the detection of H₂S and CH₃COCH₃, respectively. Pt-functionalized WO₃ hemitubes with wall thickness of 60 nm exhibited superior acetone sensitivity (R_air/R_gas = 4.11 at 2 ppm) with negligible H₂S response, and pristine WO₃ hemitubes showed a 4.90-fold sensitivity toward H₂S with minimal acetone-sensing characteristics. The detection limit (R_air/R_gas) of the fabricated sensors with Pt-functionalized WO₃ hemitubes was 1.31 for acetone of 120 ppb, and pristine WO₃ hemitubes showed a gas response of 1.23 at 120 ppb of H₂S. Long-term stability tests revealed that the remarkable selectivity has been maintained after aging for 7 months in air. The superior cross-sensitivity and response to H₂S and acetone gas offer a potential platform for application in diabetes and halitosis diagnosis.