{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,15]],"date-time":"2026-05-15T03:17:07Z","timestamp":1778815027142,"version":"3.51.4"},"reference-count":38,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2021,2,26]],"date-time":"2021-02-26T00:00:00Z","timestamp":1614297600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100008005","name":"Yonsei University College of Medicine","doi-asserted-by":"publisher","award":["6-2019-0169"],"award-info":[{"award-number":["6-2019-0169"]}],"id":[{"id":"10.13039\/501100008005","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100014188","name":"Ministry of Science and ICT, South Korea","doi-asserted-by":"publisher","award":["IITP-2020-0-01517"],"award-info":[{"award-number":["IITP-2020-0-01517"]}],"id":[{"id":"10.13039\/501100014188","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Saliva can be used for health monitoring with non-invasive wearable systems. Such devices, including electrochemical sensors, may provide a safe, fast, and cost-efficient way of detecting target ions. Although salivary ions are known to reflect those in blood, no available clinical device can detect essential ions directly from saliva. Here, we introduce an all-solid-state, flexible film sensor that allows highly accurate detection of sodium levels in saliva, comparable to those in blood. The wireless film sensor system can successfully measure sodium ions from a small volume of infants\u2019 saliva (&lt;400 \u00b5L), demonstrating its potential as a continuous health monitor. This study includes the structural characterization and error analysis of a carbon\/elastomer-based ion-selective electrode and a reference electrode to confirm the signal reliability. The sensor, composed of a pair of the electrodes, shows good sensitivity (58.9 mV\/decade) and selectivity (log K = \u22122.68 for potassium), along with a broad detection range of 5 \u00d7 10\u22125 \u2248 1 M with a low detection limit of 4.27 \u00d7 10\u22125 M. The simultaneous comparison between the film sensor and a commercial electrochemical sensor demonstrates the accuracy of the flexible sensor and a positive correlation in saliva-to-blood sodium levels. Collectively, the presented study shows the potential of the wireless ion-selective sensor system for a non-invasive, early disease diagnosis with saliva.<\/jats:p>","DOI":"10.3390\/s21051642","type":"journal-article","created":{"date-parts":[[2021,2,26]],"date-time":"2021-02-26T21:02:34Z","timestamp":1614373354000},"page":"1642","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":36,"title":["Development of Flexible Ion-Selective Electrodes for Saliva Sodium Detection"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0828-2853","authenticated-orcid":false,"given":"Hyo-Ryoung","family":"Lim","sequence":"first","affiliation":[{"name":"George W. Woodruff School of Mechanical Engineering, Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0174-1065","authenticated-orcid":false,"given":"Soon Min","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea"}]},{"given":"Musa","family":"Mahmood","sequence":"additional","affiliation":[{"name":"George W. Woodruff School of Mechanical Engineering, Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"given":"Shinjae","family":"Kwon","sequence":"additional","affiliation":[{"name":"George W. Woodruff School of Mechanical Engineering, Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3892-7560","authenticated-orcid":false,"given":"Yun-Soung","family":"Kim","sequence":"additional","affiliation":[{"name":"George W. Woodruff School of Mechanical Engineering, Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8452-2225","authenticated-orcid":false,"given":"Yongkuk","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Wichita State University, Wichita, KS 67260, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5526-3882","authenticated-orcid":false,"given":"Woon-Hong","family":"Yeo","sequence":"additional","affiliation":[{"name":"George W. Woodruff School of Mechanical Engineering, Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA 30332, USA"},{"name":"Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30322, USA"},{"name":"Parker H. Petit Institute for Bioengineering and Biosciences, Institute for Materials, Neural Engineering Center, Institute for Robotics and Intelligent Machines, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1901924","DOI":"10.1002\/adma.201901924","article-title":"Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment","volume":"32","author":"Lim","year":"2020","journal-title":"Adv. Mater."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Goldoni, R., Farronato, M., Connelly, S.T., Tartaglia, G.M., and Yeo, W.-H. (2020). 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