title: Immunoassay using probe-labelling immunogold nanoparticles with silver staining enhancement via surface-enhanced Raman scattering.
abstract: This paper reports a novel immunoassay based on surface-enhanced Raman scattering (SERS) and immunogold labelling with silver staining enhancement. Immunoreactions between immunogold colloids modified by a Raman-active probe molecule (e.g., 4-mercaptobenzoic acid) and antigens, which were captured by antibody-assembled chips such as silicon or quartz, were detected via SERS signals of Raman-active probe molecule. All the self-assembled steps were subjected to the measurements of ultraviolet-visible (UV-vis) spectra to monitor the formation of a sandwich structure onto a substrate. The immunoassay was performed by a sandwich structure consisting of three layers. The first layer was composed of immobilized antibody molecules of mouse polyclonal antibody against Hepatitis B virus surface antigen (PAb) on a silicon or quartz substrate. The second layer was the complementary Hepatitis B virus surface antigen (Antigen) molecules captured by PAb on the substrate. The third layer was composed of the probe-labelling immunogold nanoparticles, which were modified by mouse monoclonal antibody against Hepatitis B virus surface antigen (MAb) and 4-mercaptobenzoic acid (MBA) as the Raman-active probe on the surface of gold colloids. After silver staining enhancement, the antigen is identified by a SERS spectrum of MBA. A working curve of the intensity of a SERS signal at 1585 cm(-1) due to the [small nu](8a) aromatic ring vibration of MBA versus the concentration of analyte (Antigen) was obtained and the non-optimized detection limit for the Hepatitis B virus surface antigen was found to be as low as 0.5 [micro sign]g mL(-1).
authors.affiliation: Key Laboratory for Supramolecular Structure and Material of Ministry of Education, Jilin University, Changchun 130021, P. R. China.
authors.forename: Shuping
authors.initials: S
authors.lastname: Xu
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Ji
authors.forename: Weiqing
authors.initials: W
authors.lastname: Xu
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Li
authors.forename: Lianying
authors.initials: L
authors.lastname: Wang
authors.forename: Yubai
authors.initials: Y
authors.lastname: Bai
authors.forename: Bing
authors.initials: B
authors.lastname: Zhao
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Ozaki
mesh_terms: D000818:Animals; D006514:Hepatitis B Surface Antigens / Q000032:analysis*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D051379:Mice; D036103:Nanotechnology / Q000379:methods; D016622:Silver Staining; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D006514:Hepatitis B Surface Antigens