Gas-Phase Biosensing and Imaging of Human Body VOCs_**K. Itiani 1**, G. Zhang 2, K. Toma 1, T. Arakawa 1 and K. Mitsubayashi 1,2,*
* [6] Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU) 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
* [7] Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU) 2-310 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
* [8] Correspondence: m.bdi@tmd.ac.jp  
Gas-phase biosensors have been developed not only for human volatiles (acetone, methyl mercaptan, trimethylamine, ethanol, isopropanol, etc.) but also for residential harmful VOCs (formaldehyde, toluene, and nicotine) causing sick-house syndrome, etc. In particular, the bio-fluorometric (BF) gas sensors with an UV-LED excitation light and a PMT detector have indicated good sensitivity and gas-selectivity for target VOCs (formaldehyde, ethanol, acetaldehyde, acetone, isopropanol, etc.). In addition, the gas imaging system with enzyme immobilized mesh has also shown a spatio-temporal gas-imaging of human volatiles (i.e., ethanol, acetaldehyde, etc.) after drinking. In this study, the gas phase biosensor (bio-sniffer) for breath acetone and the gas imaging system (sniff-cam) for skin ethanol in the gas phase will be demonstrated as unique non-invasive biosensing approaches. The bio-sniffer for acetone vapor was constructed using a S-ADH (secondary alcohol dehydrogenase) reverse reaction by detecting the reduction in the NADH fluorescence intensity. The S-ADH immobilized sniffer was possible to monitor gaseous acetone (7 ppb to 20 ppm) continuously with a gas-selectivity based on the substrate specificity of S-ADH. The bio-sniffer allows us to measure the acetone concentration in exhaled breath from healthy subjects and diabetes (type I and II). The unique bio-fluorometric sniff-cam for gaseous ethanol was developed using alcohol dehydrogenase (ADH) immobilized mesh and the NADH imaging unit (UV-LED light array and highly sensitive camera), thus visualizing ethanol vapor not only in exhaled breath but also in transcutaneous gas after alcohol drinking. The gas-phase biosensors would be useful for non-invasive measurement of some VOC biomarkers in the medical and health care fields [1; 2; 3; 4]. ## References  
* _Iitani et al. (2019)_ Iitani, K.; Toma, K.; Arakawa, T.; Mitsubayashi, K. Ultrasensitive Sniff-Cam for Biofluorometric-Imaging of Breath Ethanol Caused by Metabolism of Intestinal Flora. _Anal. Chem._**2019**, _91_, 9458-9465. * _Arakawa et al. (2019)_ Arakawa, T.; Suzuki, T.; Tsujii, M.; Iitani, K.; Chien, P.-J. ; Ye, M.; Toma, K.; Iwasaki, Y.; Mitsubayashi, K. 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. _Biosens. Bioelectron._**2019**, _129_, 245-253. * _Chien et al. (2017)_ Chien, P.-J. ; Suzuki, T.; Tsujii, M.; Ye, M.; Minami, I.; Toda, K.; Otsuka, H.; Toma, K.; Arakawa, T.; Araki, K.; et al. 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. _Anal. Chem._**2017**, _89_, 12261-12268. * _Toma et al. (2021)_ Toma, K.; Suzuki, S.; Arakawa, T.; Iwasaki, Y.; Mitsubayashi, K. External ears for non-invasive and stable monitoring of volatile organic compounds in human blood. _Sci. Rep._**2021**, _11_, 1-8. * _Application of WD-XRF, XRD, FT-IR, and XANES to Archaeological Pottery Samples_ **K. B. Dasari 1,*, H. Cho 2, N. Lakshmana Das 3, T. Lee 4, Y. H. Yim 2 and G. M. Sun 1,*
* _Korea Atomic Energy Research Institute, Daejeon 34057, Korea_
* _Korea Research Institute of Standards and Science, Daejeon 34113, Korea_
* _GITAM (Deemed University), Visakhapatnam 530045, India_
* _Korea Basic Science Institute, Seoul 02841, Korea_
* _Correspondence: dasari@kaeri.re.kr (K.B.D. ); gmsun@kaeri.re.kr (G.M.S.