Non-invasive blood glucose testing remains a holy grail of medical technology, potentially revolutionizing the way diabetics manage their disease. Optical sensors that analyze light passing through skin have had limited success, but measuring acetone levels in exhaled breath may turn out to be a more practical solution.
It’s been known for some time that increased acetone in exhaled breath is a signature for high glucose levels within patient blood, so a sensitive breath exam may be an effective way to do indirect glucose testing. To that end, researchers from University of Pittsburgh and National Energy Technology Laboratory have developed particles made of titanium dioxide and single-walled carbon nanotubes (SWNT) that together can act as sensors for small quantities of acetone within exhaled gas. Here are some details from the study abstract in Journal of The American Chemical Society:
In this work, SWNT–TiO2 core/shell hybrid nanostructures were found to exhibit unique electrical behavior in response to UV illumination and acetone vapors. By experimental and theoretical studies of UV and acetone sensitivities of different SWNT–TiO2 hybrid systems, we established a fundamental understanding on the interfacial charge transfer between photoexcited TiO2 and SWNTs as well as the mechanism of acetone sensing. We further demonstrated a practical application of photoinduced acetone sensitivity by fabricating a microsized room temperature acetone sensor that showed fast, linear, and reversible detection of acetone vapors with concentrations in few parts per million range.
Article in Journal of The American Chemical Society: Photoinduced Charge Transfer and Acetone Sensitivity of Single-Walled Carbon Nanotube–Titanium Dioxide Hybrids