{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T01:26:36Z","timestamp":1773192396433,"version":"3.50.1"},"reference-count":22,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2018,2,3]],"date-time":"2018-02-03T00:00:00Z","timestamp":1517616000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this work, a simple electrochemical immunoassay based on platinum nanoparticles (PtNPs) using open circuit potential (OCP) detection was developed. The detection of human chorionic gonadotropin hormone (hCG) as a model analyte, was demonstrated by direct electrical detection of PtNPs in hydrazine solution using OCP measurement without any application of either potential or current to the system. Disposable screen-printed carbon electrodes (SPCEs) were utilized for the development of our immunosensor, which required a sample volume as small as 2 \u03bcL. After preparation of a sandwich-type immunosystem, hydrazine solution was dropped on the electrode\u2019s surface, which was followed immediately by electrical detection using OCP. The change of the OCP signal originated from electrocatalytic oxidation of the hydrazine on PtNPs. Under the optimal conditions of a pH of 6.0 and a hydrazine concentration of 1 mM, a detection limit of 0.28 ng mL\u22121 and a linearity of 0\u201310 ng mL\u22121 were obtained. The PtNP-based OCP method is a simpler electrochemical detection procedure than those obtained from other electrochemical methods and has an acceptable sensitivity and reproducibility. The simplicity of the detection procedure and the cost-effectiveness of the disposable SPCE illustrate the attractive benefits of this sensor. Moreover, it could be applied to a simplified and miniaturized diagnostic system with minimal user manipulation.<\/jats:p>","DOI":"10.3390\/s18020444","type":"journal-article","created":{"date-parts":[[2018,2,5]],"date-time":"2018-02-05T04:29:42Z","timestamp":1517804982000},"page":"444","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Electrochemical Immunoassay Using Open Circuit Potential Detection Labeled by Platinum Nanoparticles"],"prefix":"10.3390","volume":"18","author":[{"given":"Kanokwan","family":"Charoenkitamorn","sequence":"first","affiliation":[{"name":"School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi City, Ishikawa 923-1292, Japan"},{"name":"Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Patumwan, Bangkok 10330, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Phan","family":"Tue","sequence":"additional","affiliation":[{"name":"School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi City, Ishikawa 923-1292, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keiko","family":"Kawai","sequence":"additional","affiliation":[{"name":"School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi City, Ishikawa 923-1292, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Orawon","family":"Chailapakul","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Patumwan, Bangkok 10330, Thailand"},{"name":"National Center of Excellent of Petroleum, Petrochemicals and Advanced Materials, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuzuru","family":"Takamura","sequence":"additional","affiliation":[{"name":"School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi City, Ishikawa 923-1292, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,2,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3965","DOI":"10.1021\/ac060637m","article-title":"Electrochemical Sensors","volume":"78","author":"Bakker","year":"2006","journal-title":"Anal. 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