{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T06:01:24Z","timestamp":1771567284208,"version":"3.50.1"},"reference-count":28,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,4,6]],"date-time":"2021-04-06T00:00:00Z","timestamp":1617667200000},"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>Leptospirosis is an underestimated tropical disease caused by the pathogenic Leptospira species and responsible for several serious health problems. Here, we aimed to develop an ultrasensitive DNA biosensor for the rapid and on-site detection of the Loa22 gene of Leptospira interrogans using a gold nanoparticle\u2013carbon nanofiber composite (AuN\/CNF)-based screen-printed electrode. Cyclic voltammetry and electrochemical impedance were performed for electrochemical analysis. The sensitivity of the sensor was 5431.74 \u03bcA\/cm2\/ng with a LOD (detection limit) of 0.0077 ng\/\u03bcL using cyclic voltammetry. The developed DNA biosensor was found highly specific to the Loa22 gene of L. interrogans, with a storage stability at 4 \u00b0C for 180 days and a 6% loss of the initial response. This DNA-based sensor only takes 30 min for rapid detection of the pathogen, with a higher specificity and sensitivity. The promising results obtained suggest the application of the developed sensor as a point of care device for the diagnosis of leptospirosis.<\/jats:p>","DOI":"10.3390\/s21072552","type":"journal-article","created":{"date-parts":[[2021,4,6]],"date-time":"2021-04-06T06:05:43Z","timestamp":1617689143000},"page":"2552","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Leptospira interrogans Outer Membrane Protein-Based Nanohybrid Sensor for the Diagnosis of Leptospirosis"],"prefix":"10.3390","volume":"21","author":[{"given":"Vivek","family":"Verma","sequence":"first","affiliation":[{"name":"School of Bioengineering and Food Technology, Shoolini University, Solan 173229, HP, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2379-7422","authenticated-orcid":false,"given":"Deepak","family":"Kala","sequence":"additional","affiliation":[{"name":"Amity Center of Nanotechnology, Amity University, Gurugram 122413, HR, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shagun","family":"Gupta","sequence":"additional","affiliation":[{"name":"College of Horticulture &amp; Forestry-Neri, Hamirpur 177001, HP, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5301-484X","authenticated-orcid":false,"given":"Harsh","family":"Kumar","sequence":"additional","affiliation":[{"name":"School of Bioengineering and Food Technology, Shoolini University, Solan 173229, HP, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ankur","family":"Kaushal","sequence":"additional","affiliation":[{"name":"Amity Center of Nanotechnology, Amity University, Gurugram 122413, HR, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9664-1109","authenticated-orcid":false,"given":"Kamil","family":"Ku\u010da","sequence":"additional","affiliation":[{"name":"Center for Basic and Applied Research, Faculty of Informatics and Management, University of Hradec Kralove, 50003 Hradec Kralove, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5934-5201","authenticated-orcid":false,"given":"Nat\u00e1lia","family":"Cruz-Martins","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, University of Porto, Alameda Prof. Hern\u00e2ni Monteiro, 4200-319 Porto, Portugal"},{"name":"Institute for Research and Innovation in Health (i3S), University of Porto, 4200-135 Porto, Portugal"},{"name":"Laboratory of Neuropsychophysiology, Faculty of Psychology and Education Sciences, University of Porto, 4200-135 Porto, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3485-6408","authenticated-orcid":false,"given":"Dinesh","family":"Kumar","sequence":"additional","affiliation":[{"name":"School of Bioengineering and Food Technology, Shoolini University, Solan 173229, HP, India"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1099\/jmm.0.45860-0","article-title":"Detection of pathogenic leptospires by real-time quantitative PCR","volume":"54","author":"Levett","year":"2005","journal-title":"J. Med. Microbiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"120","DOI":"10.4172\/2155-9597.1000120","article-title":"Leptospira: Morphology, classification and pathogenesis","volume":"2","author":"Mohammed","year":"2011","journal-title":"J. Bacteriol. Parasitol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1016\/j.mimet.2005.07.015","article-title":"Evaluation of MAT, IgM ELISA and PCR methods for the diagnosis of human leptospirosis","volume":"65","author":"Ooteman","year":"2006","journal-title":"J. Microbiol. Methods"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"104727","DOI":"10.1016\/j.prevetmed.2019.104727","article-title":"Emerging Leptospira strain poses public health risk for dairy farmers in New Zealand","volume":"170","author":"Yupiana","year":"2019","journal-title":"Prev. Vet. Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"238","DOI":"10.4269\/ajtmh.15-0174","article-title":"Molecular detection of Leptospira in two returned travelers: Higher bacterial load in cerebrospinal fluid versus serum or plasma","volume":"93","author":"Waggoner","year":"2015","journal-title":"Am. J. Trop. Med. Hyg."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1515\/abm-2019-0063","article-title":"Update on molecular diagnosis of human leptospirosis","volume":"13","author":"Techawiwattanaboon","year":"2020","journal-title":"Asian Biomed."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1017-e1","DOI":"10.1016\/j.cmi.2017.10.017","article-title":"A comparison of two molecular methods for diagnosing leptospirosis from three different sample types in patients presenting with fever in Laos","volume":"24","author":"Woods","year":"2018","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Rao, M., Amran, F., and Aqilla, N. (2019). Evaluation of a rapid kit for detection of IgM against Leptospira in human. Can. J. Infect. Dis. Med. Microbiol., 2019.","DOI":"10.1155\/2019\/5763595"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.aca.2015.11.015","article-title":"Development of multiplex loop mediated isothermal amplification (m-LAMP) label-based gold nanoparticles lateral flow dipstick biosensor for detection of pathogenic Leptospira","volume":"903","author":"Najian","year":"2016","journal-title":"Anal. Chim. Acta"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41598-018-27555-2","article-title":"Diagnosis of human leptospirosis in a clinical setting: Real-time PCR high resolution melting analysis for detection of Leptospira at the onset of disease","volume":"8","author":"Esteves","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_11","first-page":"65","article-title":"Leptospirosis in humans","volume":"387","author":"Haake","year":"2015","journal-title":"Curr. Top. Microbiol. Immunol."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Ristow, P., Bourhy, P., da Cruz McBride, F.W., Figueira, C.P., Huerre, M., Ave, P., Saint Girons, I., Ko, A.I., and Picardeau, M. (2007). The OmpA-like protein Loa22 is essential for leptospiral virulence. PLoS Pathog., 3.","DOI":"10.1371\/journal.ppat.0030097"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.trac.2012.12.012","article-title":"Advances in point-of-care technologies with biosensors based on carbon nanotubes","volume":"45","author":"Justino","year":"2013","journal-title":"Trends. Anal. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Wang, D.S., and Fan, S.K. (2016). Microfluidic surface plasmon resonance sensors: From principles to point-of-care applications. Sensors, 16.","DOI":"10.3390\/s16081175"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2333","DOI":"10.1351\/pac199971122333","article-title":"Electrochemical biosensors: Recommended definitions and classification","volume":"71","author":"Thevenot","year":"1999","journal-title":"Pure Appl. Chem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s13205-020-02432-w","article-title":"AuNPs\/CNF-modified DNA biosensor for early and quick detection of O. tsutsugamushi in patients suffering from scrub typhus","volume":"10","author":"Kala","year":"2020","journal-title":"3 Biotech"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"300","DOI":"10.1016\/j.snb.2017.02.043","article-title":"Ultrasensitive nanohybrid DNA sensor for detection of pathogen to prevent damage of heart valves","volume":"246","author":"Singh","year":"2017","journal-title":"Sens. Actuator B Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1007\/s12088-016-0636-y","article-title":"Nano-Au\/cMWCNT modified speB gene specific amperometric sensor for rapidly detecting Streptococcus pyogenes causing rheumatic heart disease","volume":"57","author":"Kaushal","year":"2017","journal-title":"Indian J. Microbiol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1016\/j.ijbiomac.2017.05.041","article-title":"DNA chip based sensor for amperometric detection of infectious pathogens","volume":"103","author":"Singh","year":"2017","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1655","DOI":"10.2741\/4872","article-title":"Recent advances in the diagnosis of leptospirosis","volume":"25","author":"Verma","year":"2020","journal-title":"Front. Biosci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s13205-020-02389-w","article-title":"Diagnosis of scrub typhus: Recent advancements and challenges","volume":"10","author":"Kala","year":"2020","journal-title":"3 Biotech"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2132","DOI":"10.1016\/j.biomaterials.2008.12.065","article-title":"Conducting polymers for electrochemical DNA sensing","volume":"30","author":"Peng","year":"2009","journal-title":"Biomaterials"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1007\/s13205-019-1815-4","article-title":"Optimized DNA-based bioassay for Leptospira interrogans detection: A novel platform for leptospirosis diagnosis","volume":"9","author":"Nagraik","year":"2019","journal-title":"3 Biotech"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Singh, R.P. (2011). Prospects of nanobiomaterials for biosensing. Int. J. Electrochem. Sci.","DOI":"10.4061\/2011\/125487"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"8086","DOI":"10.3390\/ijms12118086","article-title":"An efficient method for genomic DNA extraction from different molluscs species","volume":"12","author":"Pereira","year":"2011","journal-title":"Int. J. Mol. Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"929","DOI":"10.1007\/s10529-013-1161-2","article-title":"Omp85genosensor for detection of human brain bacterial meningitis","volume":"35","author":"Dash","year":"2013","journal-title":"Biotechnol. Lett."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1016\/j.jbiosc.2019.11.003","article-title":"Nanofabricated versatile electrochemical sensor for Leptospira interrogans detection","volume":"129","author":"Nagraik","year":"2020","journal-title":"J. Biosci. Bioeng."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"111539","DOI":"10.1016\/j.bios.2019.111539","article-title":"Electrochemical immunosensor based on gold-labeled monoclonal anti-LipL32 for leptospirosis diagnosis","volume":"142","author":"Jampasa","year":"2019","journal-title":"Biosens. Bioelectron."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/7\/2552\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:58:40Z","timestamp":1760363920000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/7\/2552"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,4,6]]},"references-count":28,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2021,4]]}},"alternative-id":["s21072552"],"URL":"https:\/\/doi.org\/10.3390\/s21072552","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,4,6]]}}}