title: Immunoassay employing surface-enhanced Raman spectroscopy.
abstract: Surface-enhanced Raman scattering (SERS) was used to measure binding between biomolecules with mutual affinity, including antigen-antibody interactions. The conjugation of nitro groups onto bovine serum albumin enhanced their specific SERS activity 10(4)-fold. A dye, 2-[4'-hydroxyphenylazo]benzoic acid (HABA), with a major absorption at the Raman excitation frequency, demonstrated surface-enhanced resonance Raman scattering (SERRS) when captured from solution by avidin-coated silver films. Individual peak intensities showed a logarithmic relationship to the HABA concentration in solution over the range 10(-8) to 10(-5) M. Another resonance dye, p-dimethylaminoazobenzene (DAB) was covalently attached to an antibody directed against human thyroid stimulating hormone (TSH), without loss of antibody activity. The resultant conjugate was used in a sandwich immunoassay for TSH antigen: silver surfaces coated with anti-TSH antibody captured TSH antigen which in turn captured the DAB-anti-TSH antibody conjugate. A linear relationship was observed between the intensity of the resultant SERRS signals and the TSH antigen concentration over a range of from 4 to 60 microIU/ml. These results demonstrate the potential utility of the SERRS effect as a readout in a one-step, no wash immunoassay system.
authors.affiliation: Diagnostics Division, Abbott Laboratories, Abbott Park, Illinois 60064.
authors.forename: T E
authors.initials: TE
authors.lastname: Rohr
authors.forename: T
authors.initials: T
authors.lastname: Cotton
authors.forename: N
authors.initials: N
authors.lastname: Fan
authors.forename: P J
authors.initials: PJ
authors.lastname: Tarcha
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D001360:Avidin / Q000378:metabolism; D001391:Azo Compounds / Q000378:metabolism; D001665:Binding Sites; D001710:Biotin / Q000378:metabolism; D002417:Cattle; D004396:Coloring Agents; D004139:Dinitrofluorobenzene; D004305:Dose-Response Relationship, Drug; D007118:Immunoassay / Q000379:methods*; D007136:Immunoglobulins; D011506:Proteins / Q000032:analysis; D012710:Serum Albumin, Bovine / Q000032:analysis; D012834:Silver; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties; D013972:Thyrotropin / Q000276:immunology; D014316:Tritium
chemical_list: D000906:Antibodies; D001391:Azo Compounds; D004396:Coloring Agents; D007136:Immunoglobulins; D011506:Proteins; D014316:Tritium; D001360:Avidin; C001413:HABA; D012710:Serum Albumin, Bovine; D012834:Silver; D001710:Biotin; D013972:Thyrotropin; D004139:Dinitrofluorobenzene