{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T05:58:00Z","timestamp":1781071080532,"version":"3.54.1"},"reference-count":58,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,1,27]],"date-time":"2021-01-27T00:00:00Z","timestamp":1611705600000},"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>The protein biomarker measurement has been well-established using ELISA (enzyme-linked immunosorbent assay), which offers good sensitivity and specificity, but remains slow and expensive. Certain clinical conditions, where rapid measurement or immediate confirmation of a biomarker is paramount for treatment, necessitate more rapid analysis. Biosensors offer the prospect of reagent-less, processing-free measurements at the patient\u2019s bedside. Here, we report a platform for biosensing based on chelated Eu3+ against a range of proteins including biomarkers of cardiac injury (human myoglobin), stroke (glial fibrillary acidic protein (GFAP)), inflammation (C-reactive protein (CRP)) and colorectal cancer (carcinoembryonic antigen (CEA)). The Eu3+ ions are chelated by modified synthetic binding proteins (Affimers), which offer an alternative targeting strategy to existing antibodies. The fluorescence characteristics of the Eu3+ complex with modified Affimers against human myoglobin, GFAP, CRP and CEA were measured in human serum using \u03bbex = 395 nm, \u03bbem = 590 and 615 nm. The Eu3+-Affimer based complex allowed sensitive detection of human myoglobin, GFAP, CRP and CEA proteins as low as 100 fM in (100-fold) diluted human serum samples. The unique dependence on Eu3+ fluorescence in the visible region (590 and 615 nm) was exploited in this study to allow rapid measurement of the analyte concentration, with measurements in 2 to 3 min. These data demonstrate that the Affimer based Eu3+ complexes can function as nanobiosensors with potential analytical and diagnostic applications.<\/jats:p>","DOI":"10.3390\/s21030831","type":"journal-article","created":{"date-parts":[[2021,1,27]],"date-time":"2021-01-27T01:55:46Z","timestamp":1611712546000},"page":"831","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Affimer-Based Europium Chelates Allow Sensitive Optical Biosensing in a Range of Human Disease Biomarkers"],"prefix":"10.3390","volume":"21","author":[{"given":"Eiman","family":"Al-Enezi","sequence":"first","affiliation":[{"name":"Bionanotechnology Group, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6654-4287","authenticated-orcid":false,"given":"Alexandre","family":"Vakurov","sequence":"additional","affiliation":[{"name":"Bionanotechnology Group, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amy","family":"Eades","sequence":"additional","affiliation":[{"name":"Bionanotechnology Group, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingyu","family":"Ding","sequence":"additional","affiliation":[{"name":"Bionanotechnology Group, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9856-6755","authenticated-orcid":false,"given":"Gin","family":"Jose","sequence":"additional","affiliation":[{"name":"School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sikha","family":"Saha","sequence":"additional","affiliation":[{"name":"School of Medicine, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul","family":"Millner","sequence":"additional","affiliation":[{"name":"Bionanotechnology Group, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1690","DOI":"10.1364\/JOSAB.18.001690","article-title":"Concentration effects in the photodegradation of lissamine-functionalized neodymium complexes in polymer waveguides","volume":"18","author":"Slooff","year":"2001","journal-title":"J. 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