title: An acetone bio-sniffer (gas phase biosensor) enabling assessment of lipid metabolism from exhaled breath.
abstract: Several volatile organic compounds (VOCs) are released from human breath or skin. Like chemical substances in blood or urine, some of these vapors can provide valuable information regarding the state of the human body. A highly sensitive acetone biochemical gas sensor (bio-sniffer) was developed and used to measure exhaled breath acetone concentration, and assess lipid metabolism based on breath acetone analysis. A fiber-optic biochemical gas sensing system was constructed by attaching a flow-cell with nicotinamide adenine dinucleotide (NADH)-dependent secondary alcohol dehydrogenase (S-ADH) immobilized membrane onto a fiber-optic NADH measurement system. The NADH measurement system utilizes an ultraviolet-light emitting diode with peak emission of 335 nm as an excitation light source. NADH is consumed by the enzymatic reaction of S-ADH, and the consumption is proportional to the concentration of acetone vapor. Phosphate buffer which contained NADH was circulated into the flow-cell to rinse products and the excessive substrates from the optode. The change of fluorescent emitted from NADH is analyzed by the PMT. Hence, fluorescence intensity decreased as the acetone concentration increased. The relationship between fluorescence intensity and acetone concentration was identified from 20 ppb to 5300 ppb. This interval included the concentration of acetone vapor in the breath of healthy people and those suffering from disorders of carbohydrate metabolism. Finally, the acetone bio-sniffer was used to measure breath acetone during an exercise stress test on an ergometer after a period of fasting. The concentration of acetone in breath was shown to significantly increase after exercise. This biosensor allows rapid, highly sensitive and selective measurement of lipid metabolism.
authors.affiliation: Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: Ming
authors.initials: M
authors.lastname: Ye
authors.affiliation: Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: Po-Jen
authors.initials: PJ
authors.lastname: Chien
authors.affiliation: Department 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.
authors.forename: Koji
authors.initials: K
authors.lastname: Toma
authors.affiliation: Department 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.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Arakawa
authors.affiliation: Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; Department 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. Electronic address: m.bdi@tmd.ac.jp.
authors.forename: Kohji
authors.initials: K
authors.lastname: Mitsubayashi
mesh_terms: D000096:Acetone / Q000032:analysis*; D000429:Alcohol Oxidoreductases; D015374:Biosensing Techniques / Q000295:instrumentation*; D001944:Breath Tests / Q000379:methods*; D004800:Enzymes, Immobilized; D004867:Equipment Design; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D045853:Exhalation / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D050356:Lipid Metabolism; D009243:NAD; D055100:Optical Fibers
chemical_list: D004800:Enzymes, Immobilized; D009243:NAD; D000096:Acetone; D000429:Alcohol Oxidoreductases; C025192:isopropanol dehydrogenase (NADP)
keywords: Acetone; Biosensor; Fiber-optic; Gas sensor; Secondary alcohol dehydrogenase; Ultraviolet-light emitting diode