{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T02:56:24Z","timestamp":1776740184190,"version":"3.51.2"},"reference-count":47,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,2,24]],"date-time":"2023-02-24T00:00:00Z","timestamp":1677196800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council","doi-asserted-by":"publisher","award":["DDG-2021-00022"],"award-info":[{"award-number":["DDG-2021-00022"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council","doi-asserted-by":"publisher","award":["KP-06-DK 1\/10"],"award-info":[{"award-number":["KP-06-DK 1\/10"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Bulgarian National Science Fund","award":["DDG-2021-00022"],"award-info":[{"award-number":["DDG-2021-00022"]}]},{"name":"Bulgarian National Science Fund","award":["KP-06-DK 1\/10"],"award-info":[{"award-number":["KP-06-DK 1\/10"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>The danger of the emergence of new viral diseases and their rapid spread demands apparatuses for continuous rapid monitoring in real time. This requires the creation of new bioanalytical methods that overcome the shortcomings of existing ones and are applicable for point-of-care diagnostics. For this purpose, a variety of biosensors have been developed and tested in proof-of-concept studies, but none of them have been introduced for commercial use so far. Given the importance of the problem, in this study, long-period grating (LPG) and surface plasmon resonance (SPR) biosensors, based on antibody detection, were examined, and their capabilities for SARS-CoV-2 structural proteins detection were established. Supersensitive detections of structural proteins in the order of several femtomoles were achieved by the LPG method, while the SPR method demonstrated a sensitivity of about one hundred femtomoles. The studied biosensors are compatible in sensitivity with ELISA and rapid antigen tests but, in contrast, they are quantitative, which makes them applicable for acute SARS-CoV-2 infection detection, especially during the early stages of viral replication.<\/jats:p>","DOI":"10.3390\/bios13030318","type":"journal-article","created":{"date-parts":[[2023,2,27]],"date-time":"2023-02-27T02:15:37Z","timestamp":1677464137000},"page":"318","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Capabilities of Double-Resonance LPG and SPR Methods for Hypersensitive Detection of SARS-CoV-2 Structural Proteins: A Comparative Study"],"prefix":"10.3390","volume":"13","author":[{"given":"Tinko","family":"Eftimov","sequence":"first","affiliation":[{"name":"Photonics Research Center, Universit\u00e9 du Qu\u00e9bec en Outaouais, Rue 101 St-Jean Bosco, Gatineau, QC J8X 3G5, Canada"},{"name":"Central Laboratory of Applied Physics, Bulgarian Academy of Sciences, 61 Sanct Peterburg Blvd., 4000 Plovdiv, Bulgaria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Petia","family":"Genova-Kalou","sequence":"additional","affiliation":[{"name":"National Center of Infectious and Parasitic Diseases, 44A \u201cGen. Stoletov\u201d Blvd., 1233 Sofia, Bulgaria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Georgi","family":"Dyankov","sequence":"additional","affiliation":[{"name":"Central Laboratory of Applied Physics, Bulgarian Academy of Sciences, 61 Sanct Peterburg Blvd., 4000 Plovdiv, Bulgaria"},{"name":"Institute of Optical Materials and Technologies \u201cAcad. J. Malinowski\u201d (IOMT), Bulgarian Academy of Sciences (BAS), 109 \u201cAcad. G. Bonchev\u201d Str., 1113 Sofia, Bulgaria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wojtek J.","family":"Bock","sequence":"additional","affiliation":[{"name":"Photonics Research Center, Universit\u00e9 du Qu\u00e9bec en Outaouais, Rue 101 St-Jean Bosco, Gatineau, QC J8X 3G5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vihar","family":"Mankov","sequence":"additional","affiliation":[{"name":"Institute of Optical Materials and Technologies \u201cAcad. J. Malinowski\u201d (IOMT), Bulgarian Academy of Sciences (BAS), 109 \u201cAcad. G. Bonchev\u201d Str., 1113 Sofia, Bulgaria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sanaz","family":"Shoar Ghaffari","sequence":"additional","affiliation":[{"name":"Photonics Research Center, Universit\u00e9 du Qu\u00e9bec en Outaouais, Rue 101 St-Jean Bosco, Gatineau, QC J8X 3G5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Petar","family":"Veselinov","sequence":"additional","affiliation":[{"name":"Institute of Optical Materials and Technologies \u201cAcad. J. Malinowski\u201d (IOMT), Bulgarian Academy of Sciences (BAS), 109 \u201cAcad. G. Bonchev\u201d Str., 1113 Sofia, Bulgaria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0370-2580","authenticated-orcid":false,"given":"Alla","family":"Arapova","sequence":"additional","affiliation":[{"name":"Photonics Research Center, Universit\u00e9 du Qu\u00e9bec en Outaouais, Rue 101 St-Jean Bosco, Gatineau, QC J8X 3G5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Somayeh","family":"Makouei","sequence":"additional","affiliation":[{"name":"Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz 5166616471, Iran"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1186\/s42269-020-00341-9","article-title":"An overview on COVID-19: Reality and expectation","volume":"44","author":"Hamed","year":"2020","journal-title":"Bull. Natl. Res. 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