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Optical bio-sniffer for methyl mercaptan in halitosis
Kohji Mitsubayashi1, Takeshi Minamide, Kimio Otsuka
1Department of Biomedical Devices and Instrumentation, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan. m.bdi@tmd.ac.jp
This study developed an optical bio-sniffer using monoamine oxidase type A (MAO-A) to detect methyl mercaptan (MM), a key cause of halitosis. The device successfully monitored MM levels in breath, offering a new tool for diagnosing bad breath.
Area of Science:
- Biomedical Engineering
- Chemical Sensing
- Analytical Chemistry
Background:
- Halitosis is often caused by volatile sulfur compounds like methyl mercaptan (MM).
- Accurate detection of MM is crucial for diagnosing and managing halitosis.
- Existing methods for MM detection may lack sensitivity or real-time monitoring capabilities.
Purpose of the Study:
- To develop and evaluate an optical bio-sniffer for sensitive detection of methyl mercaptan (MM).
- To utilize monoamine oxidase type A (MAO-A) immobilized on a fiber optic oxygen sensor for MM sensing.
- To assess the device's performance in analyzing MM levels in human breath for halitosis diagnosis.
Main Methods:
- An optical bio-sniffer was constructed by immobilizing MAO-A onto a fiber optic oxygen sensor.
- A substrate regeneration cycle involving l-ascorbic acid (AsA) was employed to amplify the sensor's output.
- The sensor's characteristics were evaluated using a gas flow system, and it was applied to analyze expired air from volunteers.
Main Results:
- The optical bio-sniffer demonstrated good calibration against MM vapor (R²=0.977) across a wide concentration range (8.7–11500 ppb).
- The device showed good gas selectivity, attributed to the MAO-A enzyme's substrate specificity.
- Physiological application successfully monitored MM level changes in breath samples, correlating with halitosis thresholds.
Conclusions:
- The developed optical bio-sniffer is effective for sensitive and selective detection of methyl mercaptan.
- This technology shows promise for non-invasive, real-time monitoring of halitosis through breath analysis.
- The bio-sniffer's design and application represent a significant advancement in diagnosing breath malodor conditions.
