title: Capillary-based enzyme-linked immunosorbent assay for highly sensitive detection of thrombin-cleaved osteopontin in plasma.
abstract: In this study, a highly sensitive capillary-based enzyme-linked immunosorbent assay (ELISA) has been developed for the analysis of picomolar levels of thrombin-cleaved osteopontin (trOPN), a potential biomarker for ischemic stroke, in human plasma. Using a square capillary coated with 8.5 μg/ml anti-human trOPN capture antibody for ELISA, the linear range obtained was 2 to 16 pM trOPN antigen. This concentration range was in the detection window of trOPN antigen in plasma samples. Compared with the conventional microplate-based ELISA, the current capillary technique significantly reduced the amounts of reagent from milliliter to microliter, reduced the analysis time from 8 to 3 h, and had a better sensitivity and detection limit performance from approximately 50 pM down to 2 pM of trOPN antigen. These results indicate that this capillary-based immunoassay is a potential tool for biomarker detection and may be useful in clinical trials and medical diagnostic applications.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Osaka 599-8531, Japan.
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Funano
authors.forename: Terence G
authors.initials: TG
authors.lastname: Henares
authors.forename: Mie
authors.initials: M
authors.lastname: Kurata
authors.forename: Kenji
authors.initials: K
authors.lastname: Sueyoshi
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Endo
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hisamoto
mesh_terms: D055910:Antibodies, Immobilized / Q000276:immunology; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D001774:Blood Chemical Analysis / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D053495:Osteopontin / Q000097:blood* / Q000276:immunology / Q000378:metabolism*; D059748:Proteolysis; D013917:Thrombin / Q000378:metabolism*
chemical_list: D055910:Antibodies, Immobilized; D015415:Biomarkers; D053495:Osteopontin; D013917:Thrombin
keywords: Enzyme-linked immunosorbent assay (ELISA); Square glass capillary; Thrombin-cleaved osteopontin (trOPN)