Real-time monitoring of skin ethanol gas by a high-sensitivity gas phase biosensor (bio-sniffer) for the non-invasive evaluation of volatile blood compounds.

In this study, a highly sensitive and selective biochemical gas sensor (bio-sniffer) and real-time monitoring system with skin gas cell was constructed for the determination of ethanol gas concentration on human skin. This bio-sniffer measured the concentration of ethanol according to the change in fluorescence intensity of nicotinamide adenine dinucleotide (NADH), which is produced in an enzymatic reaction by alcohol dehydrogenase (ADH). The NADH detection system used an ultraviolet light emitting diode (UV-LED) as the excitation light, and a highly sensitive photomultiplier tube as a fluorescence intensity detector.

Biochemical Gas Sensors (Biosniffers) Using Forward and Reverse Reactions of Secondary Alcohol Dehydrogenase for Breath Isopropanol and Acetone as Potential Volatile Biomarkers of Diabetes Mellitus.

This study describes two biosniffers to determine breath acetone and isopropanol (IPA) levels and applies them for breath measurement in healthy subjects and diabetic patients. Secondary alcohol dehydrogenase (S-ADH) can reduce acetone and oxidize nicotinamide adenine dinucleotide (NADH to NAD) in a weak acid environment. NADH can be excited by 340 nm excitation lights and subsequently emit 490 nm fluorescence.

Bio-sniffer (gas-phase biosensor) with secondary alcohol dehydrogenase (S-ADH) for determination of isopropanol in exhaled air as a potential volatile biomarker.

Exhaled breath analysis has attracted lots of researchers attention in the past decades due to its advantages such as its non-invasive property and the possibility of continuous monitoring. In addition, several volatile organic compounds in breath have been identified as biomarkers for some diseases. Particularly, studies have pointed out that concentration of isopropanol (IPA) in exhaled air might relate with certain illnesses such as liver disease, chronic obstructive pulmonary (COPD), and lung cancer.