(213g) Mass Transport in Analysis of Polynucleotides by Localized Surface Plasmon Resonance in Gold Nanoparticles on Optical Fibers

Surface plasmon resonance (SPR) is collective oscillation of delocalized noble metal electrons polarized by incident resonant photons. Localized SPR (LSPR) on gold nanoparticles (AuNP) yields absorption cross-sections >106-fold higher than fluorescent dyes, allowing label-free detection of polynucleotides (PN) at levels as low as 1-500 femtomoles with point mutation selectivity factors of ~105:1. We report polynucleotide analysis via localized SPR (LSPR) of AuNP adsorbed to a multimode optical fiber (OF) using a red light emitting diode (LED). Effects of AuNP size and surface concentration on the sensitivity of PN detection via LSPR using 5- to 20-nm AuNP are measured in a microliter sample. An integrated mathematical description of mass transfer via boundary layer diffusion and kinetic adsorption is applied to quantify PN mass transfer to OF-adsorbed AuNP. Local PN concentration profiles at AuNP-OF surfaces and time constants for mass transfer rates from surrounding media are calculated. Stability of adsorbed AuNP subject to LED excitation is studied by spectral analysis. Conditions to rapidly and reproducibly detect nucleotides by OF-adsorbed AuNP are identified.