title: Sensitive determination of estriol-16-glucuronide using surface plasmon resonance sensing.
abstract: For the quantitative evaluation of low levels of an estriol metabolite of estriol (estriol-16-glucuronide (E3-16G)) in liquid media, we developed a simple and highly sensitive immunoassay using a surface plasmon resonance (SPR) biosensor which did not require any time-consuming sample pretreatment steps. E3-16G was conjugated to ovalbumin (OVA) through an oligoethylene glycol (OEG) linker to form protein conjugates (E3-16G-OEG-OVA), which were then immobilized on a carboxymethyl dextran-coated sensor chip via amine coupling to develop inhibition immunoassays. A limit of detection (LOD) of 76 pg/mL was achieved using a rabbit anti-sheep primary antibody as a binding agent. The detection limit was further improved by using synthesized gold colloids (15 nm) as high mass labels conjugated to the primary antibody. In this Au nanoparticle-enhanced assay, the concentration of E3-16G in aqueous samples could be determined in 7.5 min at a level as low as 14 pg/mL. In addition, the high stability of the E3-16G-OEG-OVA surface gave no obvious drop in antibody-binding capability after more than 1000 binding/regeneration cycles which significantly lowered the research cost.
authors.affiliation: Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
authors.forename: Xiuqian
authors.initials: X
authors.lastname: Jiang
authors.forename: Mark
authors.initials: M
authors.lastname: Waterland
authors.forename: Len
authors.initials: L
authors.lastname: Blackwell
authors.forename: Yinqiu
authors.initials: Y
authors.lastname: Wu
authors.forename: Krishanthi P
authors.initials: KP
authors.lastname: Jayasundera
authors.forename: Ashton
authors.initials: A
authors.lastname: Partridge
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D002417:Cattle; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D004964:Estriol / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D006046:Gold / Q000737:chemistry; D055767:Immobilized Proteins / Q000737:chemistry; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D018796:Immunoconjugates / Q000276:immunology; D007267:Injections; D053768:Metal Nanoparticles / Q000737:chemistry; D008970:Molecular Weight; D010047:Ovalbumin / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011817:Rabbits; D013194:Staining and Labeling; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000906:Antibodies; D004785:Environmental Pollutants; D055767:Immobilized Proteins; D018796:Immunoconjugates; D014867:Water; C012961:estriol-16 alpha-(beta-D-glucuronide); D011092:Polyethylene Glycols; D006046:Gold; D010047:Ovalbumin; D004964:Estriol