title: Size-dependent plasmonic responses of single gold nanoparticles for analysis of biorecognition.
abstract: We report the use of plasmonic responses of single gold nanoparticles (AuNPs) with various sizes for the analysis of biomolecular recognition. We also describe the relationship between particle size and plasmonic response induced by the binding of receptors and target analytes. To investigate the plasmonic response of AuNPs, Rayleigh light scattering spectra were collected from individual AuNPs using a dark-field microspectroscopy system. Using prostate-specific antigen (PSA) as a model, the linear dynamic range was obtained in the concentration range of 10(-4) to 10 ng/ml, with the smallest detectable concentration at 0.1 pg/ml corresponding to localized surface plasmon resonance (LSPR) λ(max) shifts of approximately 2.95 nm. This result indicates that individual AuNPs can be used for development of a very sensitive, robust, simple, and label-free biosensor to detect protein biomarkers. Furthermore, the method possesses great potential for monitoring other biological interactions.
authors.affiliation: Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Woo Sung
authors.initials: WS
authors.lastname: Hwang
authors.forename: Phuoc Long
authors.initials: PL
authors.lastname: Truong
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Sim
mesh_terms: D006046:Gold; D006801:Humans; D008027:Light; D053768:Metal Nanoparticles / Q000648:ultrastructure; D036103:Nanotechnology; D055620:Optical Phenomena; D010316:Particle Size; D017430:Prostate-Specific Antigen / Q000032:analysis; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000379:methods*; D000514:alpha 1-Antichymotrypsin
chemical_list: D000514:alpha 1-Antichymotrypsin; D006046:Gold; D017430:Prostate-Specific Antigen