{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T22:53:21Z","timestamp":1771023201678,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2024,5,14]],"date-time":"2024-05-14T00:00:00Z","timestamp":1715644800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Autonomous Province of Trento (Italy)","award":["LP 6\/99"],"award-info":[{"award-number":["LP 6\/99"]}]},{"name":"Autonomous Province of Trento (Italy)","award":["018\u201319"],"award-info":[{"award-number":["018\u201319"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Liquid biopsy is expected to become widespread in the coming years thanks to point of care devices, which can include label-free biosensors. The surface functionalization of biosensors is a crucial aspect that influences their overall performance, resulting in the accurate, sensitive, and specific detection of target molecules. Here, the surface of a microring resonator (MRR)-based biosensor was functionalized for the detection of protein biomarkers. Among the several existing functionalization methods, a strategy based on aptamers and mercaptosilanes was selected as the most highly performing approach. All steps of the functionalization protocol were carefully characterized and optimized to obtain a suitable protocol to be transferred to the final biosensor. The functionalization protocol comprised a preliminary plasma treatment aimed at cleaning and activating the surface for the subsequent silanization step. Different plasma treatments as well as different silanes were tested in order to covalently bind aptamers specific to different biomarker targets, i.e., C-reactive protein, SARS-CoV-2 spike protein, and thrombin. Argon plasma and 1% v\/v mercaptosilane were found as the most suitable for obtaining a homogeneous layer apt to aptamer conjugation. The aptamer concentration and time for immobilization were optimized, resulting in 1 \u00b5M and 3 h, respectively. A final passivation step based on mercaptohexanol was also implemented. The functionalization protocol was then evaluated for the detection of thrombin with a photonic biosensor based on microring resonators. The preliminary results identified the successful recognition of the correct target as well as some limitations of the developed protocol in real measurement conditions.<\/jats:p>","DOI":"10.3390\/s24103107","type":"journal-article","created":{"date-parts":[[2024,5,14]],"date-time":"2024-05-14T06:28:12Z","timestamp":1715668092000},"page":"3107","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Optimization of Surface Functionalizations for Ring Resonator-Based Biosensors"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-4837-254X","authenticated-orcid":false,"given":"Niccol\u00f2","family":"Ardoino","sequence":"first","affiliation":[{"name":"FTH S.r.l., Via Sommarive 18, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8824-2084","authenticated-orcid":false,"given":"Lorenzo","family":"Lunelli","sequence":"additional","affiliation":[{"name":"Center for Sensors & Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123 Trento, Italy"},{"name":"Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via alla Cascata 56\/C, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9338-8686","authenticated-orcid":false,"given":"Georg","family":"Pucker","sequence":"additional","affiliation":[{"name":"Center for Sensors & Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8306-8390","authenticated-orcid":false,"given":"Lia","family":"Vanzetti","sequence":"additional","affiliation":[{"name":"Center for Sensors & Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-8200-9958","authenticated-orcid":false,"given":"Rachele","family":"Favaretto","sequence":"additional","affiliation":[{"name":"FTH S.r.l., Via Sommarive 18, I-38123 Trento, Italy"},{"name":"Department of Physics, University of Trento, Via Sommarive 14, Povo, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9171-7856","authenticated-orcid":false,"given":"Laura","family":"Pasquardini","sequence":"additional","affiliation":[{"name":"Indivenire S.r.l., Via Sommarive 18, I-38123 Trento, Italy"},{"name":"Department of Engineering, University of Campania \u201cLuigi Vanvitelli\u201d, Via Roma 29, I-81031 Aversa, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3449-7874","authenticated-orcid":false,"given":"Cecilia","family":"Pederzolli","sequence":"additional","affiliation":[{"name":"Center for Sensors & Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-6134-4332","authenticated-orcid":false,"given":"Carlo","family":"Guardiani","sequence":"additional","affiliation":[{"name":"FTH S.r.l., Via Sommarive 18, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0793-7547","authenticated-orcid":false,"given":"Cristina","family":"Potrich","sequence":"additional","affiliation":[{"name":"Center for Sensors & Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123 Trento, Italy"},{"name":"Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via alla Cascata 56\/C, I-38123 Trento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,5,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1060","DOI":"10.1111\/cas.16097","article-title":"Beyond blood: Advancing the frontiers of liquid biopsy in oncology and personalized medicine","volume":"115","author":"Bao","year":"2024","journal-title":"Cancer Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/j.bj.2019.05.004","article-title":"Personalized medicine: From diagnostic to adaptive","volume":"45","author":"Braig","year":"2022","journal-title":"Biomed. 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