Highly sensitive fluorometric imaging system 'sniff-CAM' for analysis of volatile organic compounds from skin and breath

Various volatile organic compounds can be found in human transpiration, breath and body odor. Progress in the analysis of volatile organic compounds, such as those found in the breath and transdermal gas, creates an increasing potential for the application of this concept to the medical field. In this study, a novel two-dimensional fluorometric imaging system, known as a 'sniffer-cam' for ethanol vapor released from human breath and palm skin was constructed and validated. This imaging system measures ethanol vapor concentrations as intensities of fluorescence through an enzymatic reaction induced by alcohol dehydrogenase. The imaging system consisted of multiple ultra violet light emitting diode excitation sheet, an enzyme immobilized mesh substrate and a high-sensitive CCD camera. This imaging system uses alcohol dehydrogenase for recognition of ethanol vapor. It measures ethanol vapor by measuring fluorescence of nicotinamide adenine dinucleotide (NADH), which is produced by an enzymatic reaction on the mesh. The fluorescent properties of NADH (ex. 340 nm, fl. 490 nm), combining an excitation light source with a high-sensitivity camera allows us to detect and visualize NADH generated by the enzyme reaction when the ethanol gas is loaded. Based on this principle, we developed an imaging system that uses a fluorometric method for human breath and skin gas.