{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T12:36:23Z","timestamp":1768480583514,"version":"3.49.0"},"reference-count":49,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,7,8]],"date-time":"2021-07-08T00:00:00Z","timestamp":1625702400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003443","name":"Ministry of Education and Science of the Russian Federation","doi-asserted-by":"publisher","award":["075-15-2019-1671"],"award-info":[{"award-number":["075-15-2019-1671"]}],"id":[{"id":"10.13039\/501100003443","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Three techniques were compared for lowering the limit of detection (LOD) of the lateral flow immunoassay (LFIA) of the receptor-binding domain of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) based on the post-assay in situ enlargement of Au nanoparticles (Au NPs) on a test strip. Silver enhancement (growth of a silver layer over Au NPs\u2014Au@Ag NPs) and gold enhancement (growth of a gold layer over Au NPs) techniques and the novel technique of galvanic replacement of Ag by Au in Au@Ag NPs causing the formation of Au@Ag-Au NPs were performed. All the enhancements were performed on-site after completion of the conventional LFIA and maintained equipment-free assay. The assays demonstrated lowering of LODs in the following rows: 488 pg\/mL (conventional LFIA with Au NPs), 61 pg\/mL (silver enhancement), 8 pg\/mL (galvanic replacement), and 1 pg\/mL (gold enhancement). Using gold enhancement as the optimal technique, the maximal dilution of inactivated SARS-CoV-2-containing samples increased 500 times. The developed LFIA provided highly sensitive and rapid (8 min) point-of-need testing.<\/jats:p>","DOI":"10.3390\/bios11070229","type":"journal-article","created":{"date-parts":[[2021,7,8]],"date-time":"2021-07-08T12:40:27Z","timestamp":1625748027000},"page":"229","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Comparative Study of In Situ Techniques to Enlarge Gold Nanoparticles for Highly Sensitive Lateral Flow Immunoassay of SARS-CoV-2"],"prefix":"10.3390","volume":"11","author":[{"given":"Vasily G.","family":"Panferov","sequence":"first","affiliation":[{"name":"Research Center of Biotechnology of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, 119071 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nadezhda A.","family":"Byzova","sequence":"additional","affiliation":[{"name":"Research Center of Biotechnology of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, 119071 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sergey F.","family":"Biketov","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology & Biotechnology, 142279 Obolensk, Moscow Region, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3008-2839","authenticated-orcid":false,"given":"Anatoly V.","family":"Zherdev","sequence":"additional","affiliation":[{"name":"Research Center of Biotechnology of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, 119071 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4008-4918","authenticated-orcid":false,"given":"Boris B.","family":"Dzantiev","sequence":"additional","affiliation":[{"name":"Research Center of Biotechnology of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, 119071 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/j.trac.2019.04.016","article-title":"Recent advancements in structural improvements of lateral flow assays towards point-of-care testing","volume":"116","author":"Mahmoudi","year":"2019","journal-title":"TrAC Trends Anal. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3788","DOI":"10.1038\/s41596-020-0357-x","article-title":"Tutorial: Design and fabrication of nanoparticle-based lateral-flow immunoassays","volume":"15","author":"Parolo","year":"2020","journal-title":"Nat. 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