{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:27:51Z","timestamp":1785403671417,"version":"3.56.0"},"reference-count":35,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T00:00:00Z","timestamp":1777507200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science","doi-asserted-by":"publisher","award":["JP21H04888,JP22K18416, 25K24405,"],"award-info":[{"award-number":["JP21H04888,JP22K18416, 25K24405,"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]},{"award":["JP21H04888,JP22K18416, 25K24405,"],"award-info":[{"award-number":["JP21H04888,JP22K18416, 25K24405,"]}],"id":[{"id":"https:\/\/ror.org\/00hhkn466","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002241","name":"Japan Science and Technology Agency","doi-asserted-by":"publisher","award":["JPMJAX23K2"],"award-info":[{"award-number":["JPMJAX23K2"]}],"id":[{"id":"10.13039\/501100002241","id-type":"DOI","asserted-by":"publisher"}]},{"award":["JPMJAX23K2"],"award-info":[{"award-number":["JPMJAX23K2"]}],"id":[{"id":"https:\/\/ror.org\/00097mb19","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001700","name":"Ministry of Education, Culture, Sports, Science and Technology","doi-asserted-by":"publisher","award":["Cooperative Research Project of Research Center for Biomedical Engineering"],"award-info":[{"award-number":["Cooperative Research Project of Research Center for Biomedical Engineering"]}],"id":[{"id":"10.13039\/501100001700","id-type":"DOI","asserted-by":"publisher"}]},{"award":["Cooperative Research Project of Research Center for Biomedical Engineering"],"award-info":[{"award-number":["Cooperative Research Project of Research Center for Biomedical Engineering"]}],"id":[{"id":"https:\/\/ror.org\/048rj2z13","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This study presents a headset-type biofluorometric gas sensor incorporating a CMOS camera for continuous, non-invasive monitoring of transcutaneous ethanol from the ear canal. The sensor employs alcohol dehydrogenase (ADH) to catalyze the NAD+-to-NADH conversion during ethanol oxidation, enabling quantitative measurement through NADH fluorescence detection (\u03bbex = 340 nm, \u03bbem = 490 nm). The integrated system comprises a wireless CMOS camera, an ADH-immobilized cotton mesh enzyme membrane, UV-LED excitation source, optical bandpass filters, and a dual convex lens assembly housed in a 3D-printed headset powered by a lithium battery. Key improvements include a 3.5-fold enhancement in fluorescence collection efficiency achieved through optimized dual convex lens configuration. Systematic screening of seven cotton mesh materials identified Iwatsuki cotton mesh as the optimal enzyme immobilization substrate, exhibiting minimal autofluorescence and 14.2-fold higher water retention capacity compared to H-PTFE membranes. The glutaraldehyde-crosslinked ADH-immobilized cotton mesh maintained enzymatic activity for over 45 min with a 10-fold improvement in signal-to-noise ratio. The system demonstrated a dynamic detection range spanning 10 ppb to 10 ppm for gaseous ethanol and exhibited high selectivity against interfering volatile organic compounds in skin gas, including methanol, acetaldehyde, formaldehyde, and acetone. Human experiments validated the system\u2019s practical performance. Following alcohol consumption, subjects wore the device for 50 min while real-time fluorescence monitoring captured dynamic ethanol concentration changes in the ear canal. The dose-dependent fluorescence response\u2014approximately 2-fold higher at 0.4 g\/kg versus 0.04 g\/kg alcohol intake\u2014correlated well with calibration data. This headset-type biofluorometric sensor enables unrestrained continuous monitoring of ear canal ethanol, providing a novel wearable platform for alcohol metabolism assessment with potential applications in health monitoring and clinical research.<\/jats:p>","DOI":"10.3390\/s26092817","type":"journal-article","created":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T14:35:53Z","timestamp":1777559753000},"page":"2817","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Headset-Type Biofluorometric Gas Sensor with CMOS for Transcutaneous Ethanol from the Ear Canal"],"prefix":"10.3390","volume":"26","author":[{"given":"Geng","family":"Zhang","sequence":"first","affiliation":[{"name":"Laboratory for Biomaterials and Bioengineering, Institute of Integrated Research, Institute of Science Tokyo, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Di","family":"Huang","sequence":"additional","affiliation":[{"name":"Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5864-0460","authenticated-orcid":false,"given":"Kenta","family":"Ichikawa","sequence":"additional","affiliation":[{"name":"Laboratory for Biomaterials and Bioengineering, Institute of Integrated Research, Institute of Science Tokyo, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5608-8863","authenticated-orcid":false,"given":"Kenta","family":"Iitani","sequence":"additional","affiliation":[{"name":"Laboratory for Biomaterials and Bioengineering, Institute of Integrated Research, Institute of Science Tokyo, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoshikazu","family":"Nakajima","sequence":"additional","affiliation":[{"name":"Laboratory for Biomaterials and Bioengineering, Institute of Integrated Research, Institute of Science Tokyo, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0709-4957","authenticated-orcid":false,"given":"Kohji","family":"Mitsubayashi","sequence":"additional","affiliation":[{"name":"Laboratory for Biomaterials and Bioengineering, Institute of Integrated Research, Institute of Science Tokyo, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4257","DOI":"10.1021\/acsomega.1c05948","article-title":"Breath Analysis for the In Vivo Detection of Diabetic Ketoacidosis","volume":"7","author":"Sha","year":"2022","journal-title":"ACS Omega"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Awchi, M., Singh, K.D., Brenner, S.B., Burckhardt, M.-A., Hess, M., Zeng, J., Datta, A.N., Frey, U., Zumsteg, U., and Szinnai, G. 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