Related Experiment Video
Updated: Jan 8, 2026
High-resolution Respirometry to Measure Mitochondrial Function of Intact Beta Cells in the Presence of Natural Compounds
Published on: January 23, 2018
High-sensitivity isopropanol Biomeasurement using enzyme cycling reactions
Geng Zhang1, Kenta Ichikawa1, Kenta Iitani1
1Department of Biomedical Devices and Instrumentation, Laboratory for Biomaterials and Bioengineering, Institute of Integrated Research, Institute of Science Tokyo, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan.
None:
Elevated isopropanol (IPA) levels in biological fluids are potential biomarkers for ketoacidosis. This study developed a high-sensitivity IPA detection system using an enzyme cycling reaction with secondary alcohol dehydrogenase (S-ADH). The system employs a dual-coenzyme mechanism where IPA is repeatedly oxidized and regenerated through sequential reactions with thio-NAD+ and NADH, producing accumulating thio-NADH that is measured spectrophotometrically at 405 nm. After optimization of reaction conditions (pH 8.5, 500 μM thio-NAD+, 50 μM NADH), the cycling reaction achieved a 6-fold improvement in sensitivity compared to single-step detection. The detection range expanded from 22.5 μM-1 mM to 3.9 μM-1 mM, encompassing physiological IPA concentrations in healthy human saliva (5.51-24.6 μM). This enhanced sensitivity enables non-invasive ketoacidosis monitoring through saliva analysis, demonstrating the potential of enzyme cycling-based biosensors for clinical applications.
