title: Enhanced surface plasmon resonance by Au nanoparticles immobilized on a dielectric SiO2 layer on a gold surface.
abstract: This paper introduces strategies for enhancement of a surface plasmon resonance (SPR) signal by adopting colloidal gold nanoparticles (AuNPs) and a SiO(2) layer on a gold surface. AuNPs on SiO(2) on a gold surface were compared with an unmodified gold surface and a SiO(2) layer on a gold surface with no AuNPs attached. The modified surfaces showed significant changes in SPR signal when biomolecules were attached to the surface as compared with an unmodified gold surface. The detection limit of AuNPs immobilized on a SPR chip was 0.1 ng mL(-1) for the prostate-specific antigen (PSA), a cancer marker, as measured with a spectrophotometer. Considering that the conventional ELISA method can detect approximately 10 ng mL(-1) of PSA, the strategy described here is much more sensitive (approximately 100 fold). The enhanced shift of the absorption curve resulted from the coupling of the surface and particle plasmons by the SiO(2) layer and the AuNPs on the gold surface.
authors.affiliation: Department of Biosystems and Biomaterials Science and Engineering, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Jaeyeon
authors.initials: J
authors.lastname: Jung
authors.forename: Kyunga
authors.initials: K
authors.lastname: Na
authors.forename: Jonghwan
authors.initials: J
authors.lastname: Lee
authors.forename: Ki-Woo
authors.initials: KW
authors.lastname: Kim
authors.forename: Jinho
authors.initials: J
authors.lastname: Hyun
mesh_terms: D006046:Gold / Q000737:chemistry*; D006801:Humans; D008297:Male; D053768:Metal Nanoparticles / Q000737:chemistry*; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011471:Prostatic Neoplasms / Q000175:diagnosis; D012822:Silicon Dioxide / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D006046:Gold; D012822:Silicon Dioxide; D017430:Prostate-Specific Antigen