title: Surface plasmon resonance-based immunoassay for human fetuin A.
abstract: This article describes a highly-sensitive surface plasmon resonance (SPR)-based immunoassay (IA) for human fetuin A (HFA), a specific biomarker for atherosclerosis and hepatocellular carcinoma. The assay is based on a novel immobilization procedure that simply involves the dilution of an anti-HFA capture antibody (Ab) in 1% (v/v) 3-aminopropyltriethoxysilane (APTES), followed by its dispensing on a KOH-treated gold (Au)-coated SPR chip and incubation for 30 min. The developed SPR IA detected 0.3-20 ng mL(-1) of HFA with a limit of detection and sensitivity of 0.7 ng mL(-1) and 1 ng mL(-1), respectively. The highly-simplified Ab immobilization procedure is also 5-fold more rapid than conventional procedures. It leads to the leach-proof binding of the capture Ab, which means that the developed SPR IA is highly cost-effective, as the Ab-bound SPR chip could be reused for many repeated HFA IAs after regeneration with 10 mM glycine-HCl, pH 2.0. The Ab-bound SPR chip, stored at 4 °C, lost only 18% of its original activity after 4 months. For the detection of HFA spiked in diluted human whole blood and plasma, the results obtained by the developed SPR IA agreed well with the commercial HFA sandwich ELISA.
authors.affiliation: HSG-IMIT - Institut für Mikro - und Informationstechnik, Georges-Koehler Allee 103, 79110 Freiburg, Germany. sandeep.kumar.vashist@hsg-imit.de.
authors.forename: S K
authors.initials: SK
authors.lastname: Vashist
authors.forename: E M
authors.initials: EM
authors.lastname: Schneider
authors.forename: J H T
authors.initials: JH
authors.lastname: Luong
mesh_terms: D006801:Humans; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D020349:Surface Plasmon Resonance / Q000379:methods*; D060749:alpha-2-HS-Glycoprotein / Q000032:analysis*
chemical_list: D060749:alpha-2-HS-Glycoprotein