title: Europium nanoparticle-based simple to perform dry-reagent immunoassay for the detection of hepatitis B surface antigen.
abstract: Hepatitis B infection, caused by hepatitis B virus (HBV), presents a huge global health burden. Serological diagnosis of HBV mainly relies on the detection of hepatitis B surface antigen (HBsAg). Although there are high sensitivity commercial HBsAg enzyme immunoassays (EIAs) available, many low-resource laboratories lacking trained technicians continue to use rapid point-of-care assays with low sensitivities for HBsAg detection, due to their simplicity to operate. We developed a time-resolved fluorometric dry-reagent HBsAg immunoassay which meets the detection limit of high sensitivity EIAs but is simple to operate. To develop the assay, anti-HBsAg monoclonal antibody coated on europium nanoparticles was dried atop of biotinylated anti-HBsAg polyclonal antibody immobilized on streptavidin-coated microtiter wells. To test a sample in dry-reagent assay, serum sample and assay buffer were added to the wells, incubated, washed and europium signals were measured. The assay showed a detection limit of 0.25 ng/ml using HBsAg spiked in serum sample. When evaluated with 24 HBV positive and 37 negative serum samples, assay showed 100% sensitivity and specificity. Assay wells are stable for at least 26 weeks when stored at 4°C, and can tolerate elevated temperatures of up to 35°C for two weeks. The developed assay has high potential to be used in low-resource laboratories.
authors.affiliation: Department of Biotechnology, University of Turku, Turku, Finland. Electronic address: talshe@utu.fi.
authors.forename: Sheikh M
authors.initials: SM
authors.lastname: Talha
authors.affiliation: Department of Biotechnology, University of Turku, Turku, Finland.
authors.forename: Teppo
authors.initials: T
authors.lastname: Salminen
authors.affiliation: Department of Biotechnology, University of Turku, Turku, Finland.
authors.forename: Etvi
authors.initials: E
authors.lastname: Juntunen
authors.affiliation: Department of Biotechnology, University of Turku, Turku, Finland.
authors.forename: Anni
authors.initials: A
authors.lastname: Spangar
authors.affiliation: Recombinant Gene Products Group, International Centre for Genetic Engineering & Biotechnology, Aruna Asaf Ali Marg, New Delhi, India; Center for Advanced Sensor Technology and Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, USA.
authors.forename: Chandrasekhar
authors.initials: C
authors.lastname: Gurramkonda
authors.affiliation: Department of Virology, University of Turku, Turku, Finland.
authors.forename: Tytti
authors.initials: T
authors.lastname: Vuorinen
authors.affiliation: Recombinant Gene Products Group, International Centre for Genetic Engineering & Biotechnology, Aruna Asaf Ali Marg, New Delhi, India; Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, India; Department of Paediatrics, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Navin
authors.initials: N
authors.lastname: Khanna
authors.affiliation: Department of Biotechnology, University of Turku, Turku, Finland.
authors.forename: Kim
authors.initials: K
authors.lastname: Pettersson
mesh_terms: D005063:Europium; D005470:Fluorometry / Q000379:methods*; D006509:Hepatitis B / Q000175:diagnosis*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007202:Indicators and Reagents; D053758:Nanoparticles; D012680:Sensitivity and Specificity
chemical_list: D006514:Hepatitis B Surface Antigens; D007202:Indicators and Reagents; D005063:Europium
keywords: Assay; Diagnostics; Europium; HBsAg; Hepatitis B virus; Time-resolved