title: A protein assay based on colloidal gold conjugates with trypsin.
abstract: The standard sol particle immunoassay (SPIA) is based on a biospecific aggregation of gold nanoparticle conjugates, followed by conventional spectrophotometry. Here we propose a novel SPIA format that uses microtitration immunological plates and an enzyme-linked immunosorbent assay reader. The novel and standard assays are exemplified by determination of immunoglobulin G by using 15-nm colloidal gold-protein A conjugates. We also describe a novel sol particle-trypsin assay using conjugates of gold nanoparticles with trypsin. The method is based on measuring spectral extinction changes caused by the addition of protein to a conjugate solution. The changes in the extinction spectra are presumed to be related to aggregation of gold nanoparticles caused by polyvalent binding of protein molecules to the trypsin molecules of the conjugates.
authors.affiliation: Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, Saratov 410049, Russia.
authors.forename: Lev A
authors.initials: LA
authors.lastname: Dykman
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Bogatyrev
authors.forename: Boris N
authors.initials: BN
authors.lastname: Khlebtsov
authors.forename: Nikolai G
authors.initials: NG
authors.lastname: Khlebtsov
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D017979:Gold Colloid; D007074:Immunoglobulin G; D011506:Proteins / Q000032:analysis*; D013205:Staphylococcal Protein A; D014357:Trypsin
chemical_list: D017979:Gold Colloid; D007074:Immunoglobulin G; D011506:Proteins; D013205:Staphylococcal Protein A; D014357:Trypsin