title: Hyper-Rayleigh scattering of protein-modified gold nanoparticles.
abstract: The nonlinear optical properties of protein-modified gold nanoparticles has been studied by the hyper-Rayleigh scattering (HRS) technique. HRS signals from the nanoparticles coated with goat-anti-human IgG have been obtained when pumped with a laser pulse with a wavelength of 1064 nm. The HRS signals of gold nanoparticles with IgG were larger than those of bare gold nanoparticles. This can be explained by a noncentrosymmetric effect. It was also found that the HRS signals from the IgG-coated gold nanoparticles could be greatly increased when the antigen was added due to gold nanoparticle aggregation. Our experiment found that the HRS method could produce a measurable signal with 10 microg/ml antigen added, while the colorimetric method using UV spectrum detection required 100 microg/ml of added antigen. The results show that the HRS measurement of immunogold nanoparticles could become a potential immunoassay in determining small levels of antigen in aqueous samples.
authors.affiliation: National Laboratory of Molecular and Biomolecular Electronics, Southeast University, Nanjing 210096, China.
authors.forename: Chun Xiu
authors.initials: CX
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Zu Ming
authors.initials: ZM
authors.lastname: Tang
authors.forename: Zu Hong
authors.initials: ZH
authors.lastname: Lu
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000378:metabolism; D000941:Antigens / Q000032:analysis; D015374:Biosensing Techniques; D006046:Gold / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D007834:Lasers; D008027:Light; D043942:Nanotubes / Q000737:chemistry*; D012542:Scattering, Radiation; D012815:Signal Processing, Computer-Assisted; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000941:Antigens; D007074:Immunoglobulin G; D012996:Solutions; C048844:anti-IgG; D006046:Gold