{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T13:35:40Z","timestamp":1790688940857,"version":"4.1.0"},"reference-count":47,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,7,19]],"date-time":"2025-07-19T00:00:00Z","timestamp":1752883200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union\u2019s HORIZON-MSCA Doctoral Networks 2021 program","award":["101071485"],"award-info":[{"award-number":["101071485"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Early diagnosis of Alzheimer\u2019s disease (AD) is essential for effective treatment; however current diagnostic methods are often complex, costly, and unsuitable for point-of-care testing. Graphene-based biosensors offer an alternative due to their affordability, versatility, and high conductivity. However, graphene\u2019s conductivity can be compromised when its carbon lattice is oxidized to introduce functional groups for biomolecule immobilization. This study addresses this challenge by developing an electrochemical immunosensor using carboxyl-modified commercial graphene foam (COOH-GF) electrodes. The conductivity of graphene is preserved by enabling efficient COOH modification through \u03c0\u2013\u03c0 non-covalent interactions, while antibody immobilization is optimized via EDC-NHS carbodiimide chemistry. The immunosensor detects tau-441, an AD biomarker, using differential pulse voltammetry (DPV), achieving a detection range of 1 fM\u20131 nM, with a limit of detection (LOD) of 0.14 fM both in PBS and human serum. It demonstrates high selectivity against other AD-related proteins, including tau-217, tau-181, amyloid beta (A\u03b21-40 and A\u03b21-42), and 1% BSA. These findings underscore its potential as a highly sensitive, cost-effective tool for early AD diagnosis.<\/jats:p>","DOI":"10.3390\/bios15070465","type":"journal-article","created":{"date-parts":[[2025,7,21]],"date-time":"2025-07-21T08:47:14Z","timestamp":1753087634000},"page":"465","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Electrochemical Immunosensor Using COOH-Functionalized 3D Graphene Electrodes for Sensitive Detection of Tau-441 Protein"],"prefix":"10.3390","volume":"15","author":[{"given":"Sophia","family":"Nazir","sequence":"first","affiliation":[{"name":"Nanomaterials and Devices Laboratory (NMD), School of Engineering, Computing and Mathematics, University of Plymouth, Devon PL4 8AA, UK"},{"name":"School of Engineering, Computing and Mathematics, University of Plymouth, Devon PL4 8AA, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-5564-4019","authenticated-orcid":false,"given":"Muhsin","family":"Dogan","sequence":"additional","affiliation":[{"name":"Nanomaterials and Devices Laboratory (NMD), School of Engineering, Computing and Mathematics, University of Plymouth, Devon PL4 8AA, UK"},{"name":"Biomedical Engineering, Engineering and Architecture Faculty, Izmir Bakircay University, 35665 Izmir, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yinghui","family":"Wei","sequence":"additional","affiliation":[{"name":"School of Engineering, Computing and Mathematics, University of Plymouth, Devon PL4 8AA, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Genhua","family":"Pan","sequence":"additional","affiliation":[{"name":"Nanomaterials and Devices Laboratory (NMD), School of Engineering, Computing and Mathematics, University of Plymouth, Devon PL4 8AA, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1186\/1750-1326-4-27","article-title":"Neurodegeneration in Alzheimer\u2019s disease: Caspases and synaptic element interdependenc","volume":"4","author":"Bredesen","year":"2009","journal-title":"Mol. 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