{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T11:35:15Z","timestamp":1768822515522,"version":"3.49.0"},"reference-count":36,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2021,11,30]],"date-time":"2021-11-30T00:00:00Z","timestamp":1638230400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Detection methods for monitoring infectious pathogens has never been more important given the need to contain the spread of the COVID-19 pandemic. Herein we propose a highly sensitive magnetic-focus-enhanced lateral flow assay (mLFA) for the detection of SARS-CoV-2. The proposed mLFA is simple and requires only lateral flow strips and a reusable magnet to detect very low concentrations of the virus particles. The magnetic focus enhancement is achieved by focusing the SARS-CoV-2 conjugated magnetic probes in the sample placed in the lateral flow (LF) strips for improved capture efficiency, while horseradish peroxidase (HRP) was used to catalyze the colorimetric reaction for the amplification of the colorimetric signal. With the magnetic focus enhancement and HRP-based amplification, the mLFA could yield a highly sensitive technology for the recognition of SARS-CoV-2. The developed methods could detect as low as 400 PFU\/mL of SARS-CoV-2 in PBS buffer based on the visible blue dots on the LF strips. The mLFA could recognize 1200 PFU\/mL of SARS-CoV-2 in saliva samples. With clinical nasal swab samples, the proposed mLFA could achieve 66.7% sensitivity and 100% specificity.<\/jats:p>","DOI":"10.3390\/bios11120488","type":"journal-article","created":{"date-parts":[[2021,11,30]],"date-time":"2021-11-30T20:29:27Z","timestamp":1638304167000},"page":"488","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Paper-Based Test for Rapid On-Site Screening of SARS-CoV-2 in Clinical Samples"],"prefix":"10.3390","volume":"11","author":[{"given":"Wen","family":"Ren","sequence":"first","affiliation":[{"name":"Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA"},{"name":"Biomedical Research Center, Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL 61801, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0630-1520","authenticated-orcid":false,"given":"Joseph","family":"Irudayaraj","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA"},{"name":"Biomedical Research Center, Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL 61801, USA"},{"name":"Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA"},{"name":"Cancer Center at Illinois (CCIL), University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2000045","DOI":"10.2807\/1560-7917.ES.2020.25.3.2000045","article-title":"Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR","volume":"25","author":"Corman","year":"2020","journal-title":"Eurosurveillance"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1248","DOI":"10.1016\/j.cmi.2020.06.009","article-title":"Large-scale implementation of pooled RNA extraction and RT-PCR for SARS-CoV-2 detection","volume":"26","author":"Klochendler","year":"2020","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"950","DOI":"10.1111\/1751-7915.13586","article-title":"RT-LAMP for rapid diagnosis of coronavirus SARS-CoV-2","volume":"13","author":"Huang","year":"2020","journal-title":"Microb. Biotechnol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"773","DOI":"10.1016\/j.cmi.2020.04.001","article-title":"Rapid and visual detection of 2019 novel coronavirus (SARS-CoV-2) by a reverse transcription loop-mediated isothermal amplification assay","volume":"26","author":"Yan","year":"2020","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1140","DOI":"10.1038\/s41551-020-00603-x","article-title":"Clinical validation of a Cas13-based assay for the detection of SARS-CoV-2 RNA","volume":"4","author":"Patchsung","year":"2020","journal-title":"Nat. Biomed. Eng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"5367","DOI":"10.1002\/ange.202014506","article-title":"Simultaneous dual-gene diagnosis of SARS-CoV-2 based on CRISPR\/Cas9-mediated lateral flow assay","volume":"133","author":"Xiong","year":"2021","journal-title":"Angew. Chem."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1038\/s41587-020-0513-4","article-title":"CRISPR-Cas12-based detection of SARS-CoV-2","volume":"38","author":"Broughton","year":"2020","journal-title":"Nat. Biotechnol."},{"key":"ref_8","unstructured":"(2021, September 20). Tracking SARS-CoV-2 Variants. Available online: https:\/\/www.who.int\/en\/activities\/tracking-SARS-CoV-2-variants\/."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e2105968118","DOI":"10.1073\/pnas.2105968118","article-title":"Reverse-transcribed SARS-CoV-2 RNA can integrate into the genome of cultured human cells and can be expressed in patient-derived tissues","volume":"118","author":"Zhang","year":"2021","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"100831","DOI":"10.1016\/j.nantod.2019.100831","article-title":"Strategies for developing sensitive and specific nanoparticle-based lateral flow assays as point-of-care diagnostic device","volume":"30","author":"Soh","year":"2020","journal-title":"Nano Today"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1518","DOI":"10.1002\/jmv.25727","article-title":"Development and clinical application of a rapid IgM-IgG combined antibody test for SARS-CoV-2 infection diagnosis","volume":"92","author":"Li","year":"2020","journal-title":"J. Med. Virol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"4255","DOI":"10.1039\/D0LC00828A","article-title":"A point-of-care selenium nanoparticle-based test for the combined detection of anti-SARS-CoV-2 IgM and IgG in human serum and blood","volume":"20","author":"Wang","year":"2020","journal-title":"Lab Chip"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1021\/ac8020592","article-title":"Aptamer-functionalized gold nanoparticles as probes in a dry-reagent strip biosensor for protein analysis","volume":"81","author":"Xu","year":"2009","journal-title":"Anal. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1638","DOI":"10.1039\/C5LC00055F","article-title":"Multicolored silver nanoparticles for multiplexed disease diagnostics: Distinguishing dengue, yellow fever, and Ebola viruses","volume":"15","author":"Yen","year":"2015","journal-title":"Lab Chip"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"324","DOI":"10.1016\/j.bios.2018.10.066","article-title":"Plasmonic enhancement in lateral flow sensors for improved sensing of E. coli O157: H7","volume":"126","author":"Ren","year":"2019","journal-title":"Biosens. Bioelectron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"7941","DOI":"10.1021\/ac201950g","article-title":"Enhanced Sensitivity of Lateral Flow Tests Using a Two-Dimensional Paper Network Format","volume":"83","author":"Fu","year":"2011","journal-title":"Anal. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1016\/j.foodcont.2015.02.019","article-title":"Gold nanoparticles-based lateral flow immunoassay with silver staining for simultaneous detection of fumonisin B-1 and deoxynivalenol","volume":"54","author":"Yu","year":"2015","journal-title":"Food Control"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1016\/j.ijfoodmicro.2015.04.032","article-title":"Rapid pathogen detection by lateral-flow immunochromatographic assay with gold nanoparticle-assisted enzyme signal amplification","volume":"206","author":"Cho","year":"2015","journal-title":"Int. J. Food Microbiol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3313","DOI":"10.1007\/s00216-013-6742-3","article-title":"Lateral-flow enzyme immunoconcentration for rapid detection of Listeria monocytogenes","volume":"405","author":"Cho","year":"2013","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"7008","DOI":"10.1021\/ac101405a","article-title":"Rapid and Sensitive Detection of Protein Biomarker Using a Portable Fluorescence Biosensor Based on Quantum Dots and a Lateral Flow Test Strip","volume":"82","author":"Li","year":"2010","journal-title":"Anal. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1039\/C9AY02247C","article-title":"A multicolor multiplex lateral flow assay for high-sensitivity analyte detection using persistent luminescent nanophosphors","volume":"12","author":"Danthanarayana","year":"2020","journal-title":"Anal. Method."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ross, G.M.S., Bremer, M., Wichers, J.H., van Amerongen, A., and Nielen, M.W.F. (2018). Rapid Antibody Selection Using Surface Plasmon Resonance for High-Speed and Sensitive Hazelnut Lateral Flow Prototypes. Biosensors-Basel, 8.","DOI":"10.3390\/bios8040130"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"714","DOI":"10.1016\/j.msec.2009.01.011","article-title":"Study of superparamagnetic nanoparticles as labels in the quantitative lateral flow immunoassay","volume":"29","author":"Wang","year":"2009","journal-title":"Mater. Sci. Eng. C"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1009","DOI":"10.1021\/ac504552r","article-title":"Two orders of magnitude improvement in detection limit of lateral flow assays using lsotachophoresis","volume":"87","author":"Moghadam","year":"2015","journal-title":"Anal. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"4406","DOI":"10.1039\/C4LC00972J","article-title":"Improving sensitivity of gold nanoparticle-based lateral flow assays by using wax-printed pillars as delay barriers of microfluidics","volume":"14","author":"Rivas","year":"2014","journal-title":"Lab Chip"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1360","DOI":"10.1038\/s41598-017-01558-x","article-title":"Improved analytical sensitivity of lateral flow assay using sponge for HBV nucleic acid detection","volume":"7","author":"Tang","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4465","DOI":"10.1039\/C4LC00734D","article-title":"1000-fold sample focusing on paper-based microfluidic devices","volume":"14","author":"Rosenfeld","year":"2014","journal-title":"Lab Chip"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"5829","DOI":"10.1021\/ac500780w","article-title":"Isotachophoretic preconcenetration on paper-based microfluidic devices","volume":"86","author":"Moghadam","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4930","DOI":"10.1039\/C5CC10240E","article-title":"Ultrasensitive detection of microbial cells using magnetic focus enhanced lateral flow sensors","volume":"52","author":"Ren","year":"2016","journal-title":"Chem. Commun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2876","DOI":"10.1021\/acs.analchem.8b04848","article-title":"Magnetic focus lateral flow sensor for detection of cervical cancer biomarkers","volume":"91","author":"Ren","year":"2019","journal-title":"Anal. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"11095","DOI":"10.1021\/acsomega.1c01307","article-title":"16S rRNA Monitoring Point-of-Care Magnetic Focus Lateral Flow Sensor","volume":"6","author":"Ren","year":"2021","journal-title":"ACS Omega"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"104384","DOI":"10.1016\/j.jcv.2020.104384","article-title":"Comparing the analytical performance of three SARS-CoV-2 molecular diagnostic assays","volume":"127","author":"Uhteg","year":"2020","journal-title":"J. Clin. Virol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1016\/j.matchemphys.2010.03.080","article-title":"Synthesis, conductivity and dielectric characterization of salicylic acid-Fe3O4 nanocomposite","volume":"123","author":"Unal","year":"2010","journal-title":"Mater. Chem. Phys."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"938","DOI":"10.1039\/C4AN01897D","article-title":"A native chromatin extraction method based on salicylic acid coated magnetic nanoparticles and characterization of chromatin","volume":"140","author":"Zhou","year":"2015","journal-title":"Analyst"},{"key":"ref_35","unstructured":"(2021, June 12). Interim Laboratory Biosafety Guidelines for Handling and Processing Specimens Associated with Coronavirus Disease 2019 (COVID-19), Available online: https:\/\/www.cdc.gov\/coronavirus\/2019-nCoV\/lab\/lab-biosafety-guidelines.html."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"4812","DOI":"10.1038\/s41467-020-18611-5","article-title":"Massive and rapid COVID-19 testing is feasible by extraction-free SARS-CoV-2 RT-PCR","volume":"11","author":"Smyrlaki","year":"2020","journal-title":"Nat. Commun."}],"container-title":["Biosensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6374\/11\/12\/488\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:38:08Z","timestamp":1760168288000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6374\/11\/12\/488"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,11,30]]},"references-count":36,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2021,12]]}},"alternative-id":["bios11120488"],"URL":"https:\/\/doi.org\/10.3390\/bios11120488","relation":{},"ISSN":["2079-6374"],"issn-type":[{"value":"2079-6374","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,11,30]]}}}