title: Estimation of dielectric function of biotin-capped gold nanoparticles via signal enhancement on surface plasmon resonance.
abstract: Biotin-capped gold nanoparticles assembled on flat gold with volume fraction f are studied by surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM) in order to estimate the dielectric function of the gold nanoparticles based on the Maxwell-Garnett (MG) theory. The complex dielectric function (epsilon',epsilon'') of the spherical nanoparticles at three representative wavelengths in the vis-near-IR region, i.e., lambda = 543, 632.8, and 1152 nm, is estimated for a surface homogeneously covered with nanoparticles in order to discuss the wavelength dependence of the dielectric function. The SPR response of a surface covered with particles in 2D aggregates is also analyzed. The experimental SPR curve of the particle aggregates deviates from the theoretical predictions, suggesting dipole interactions between particles.
authors.affiliation: Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Nagatsuta-cho, Yokohama, Kanagawa 226-8502, Japan.
authors.forename: Xinheng
authors.initials: X
authors.lastname: Li
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tamada
authors.forename: Akira
authors.initials: A
authors.lastname: Baba
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Knoll
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hara
mesh_terms: D000327:Adsorption; D001710:Biotin / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000295:instrumentation / Q000379:methods; D010316:Particle Size; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods*; D013499:Surface Properties
chemical_list: D001710:Biotin; D006046:Gold