title: Antibody tagged gold nanoparticles as scattering probes for the pico molar detection of the proteins in blood serum using nanoparticle tracking analyzer.
abstract: We report a rapid one-step immunoassay to detect protein using antibody conjugated gold nanoparticles (AbGNPs) where the targeted protein concentration was determined by analyzing the gold nanoparticle aggregation caused by antibody-antigen interactions using nanoparticles tracking analysis (NTA) technique. The sandwich structure constituting the binding of the targeted human IgG to the gold nanoparticle conjugates with goat anti human monoclonal IgG (AbGNPs) was confirmed by transmission electron microscopy. The binding of human IgG (antigen, mentioned hence forth as AT) induce AbGNPs to form dimers or trimers through a typical antibody-antigen-antibody sandwich structure that can be analyzed for the sensitive determination on the basis of change in hydrodynamic diameter of AbGNPs. By this method the minimum detectable concentration of AT is found to be below 2pg/ml. We expect that a significant change in the hydrodynamic diameter of AbGNP could form the basis for the rapid one-step immunoassay development.
authors.affiliation: Department of Analytical Chemistry, The Institute of Science, 15 Madame Cama Road, Mumbai 400032, India.
authors.forename: Sahebrao Balaso
authors.initials: SB
authors.lastname: Kashid
authors.affiliation: Department of Biochemistry, Ahmednagar College, Ahmednagar, India.
authors.forename: Rajesh D
authors.initials: RD
authors.lastname: Tak
authors.affiliation: Department of Botany, The Institute of Science, 15 Madame Cama Road, Mumbai 400032, India. Electronic address: r_raut@rediffmail.com.
authors.forename: Rajesh Warluji
authors.initials: RW
authors.lastname: Raut
mesh_terms: D001798:Blood Proteins / Q000378:metabolism*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission
chemical_list: D001798:Blood Proteins; D006046:Gold
keywords: Antibody tagged GNPs; Antigen detection; NTA; Pico molar detection