Nanohole-based surface plasmon resonance instruments with improved spectral resolution quantify a broad range of antibody-ligand binding kinetics

Hyungsoon Im, Jamie N. Sutherland, Jennifer A. Maynard, Sang Hyun Oh

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98 Scopus citations

Abstract

We demonstrate an affordable low-noise surface plasmon resonance (SPR) instrument based on extraordinary optical transmission (EOT) in metallic nanohole arrays and quantify a broad range of antibody-ligand binding kinetics with equilibrium dissociation constants ranging from 200 pM to 40 nM. This nanohole-based SPR instrument is straightforward to construct, align, and operate, since it is built around a standard microscope and a portable fiber-optic spectrometer. The measured refractive index resolution of this platform is 3.1 × 10 -6 without on-chip cooling, which is among the lowest reported for SPR sensors based on EOT. This is accomplished via rapid full-spectrum acquisition in 10 ms followed by frame averaging of the EOT spectra, which is made possible by the production of template-stripped gold nanohole arrays with homogeneous optical properties over centimeter-sized areas. Sequential SPR measurements are performed using a 12-channel microfluidic flow cell after optimizing surface modification protocols and antibody injection conditions to minimize masstransport artifacts. The immobilization of a model ligand, the protective antigen of anthrax on the gold surface, is monitored in real-time with a signal-to-noise ratio of ∼860. Subsequently, real-time binding kinetic curves were measured quantitatively between the antigen and a panel of small, 25 kDa single-chain antibodies at concentrations down to 1 nM. These results indicate that nanohole-based SPR instruments have potential for quantitative antibody screening and as a general-purpose platform for integrating SPR sensors with other bioanalytical tools.

Original languageEnglish (US)
Pages (from-to)1941-1947
Number of pages7
JournalAnalytical Chemistry
Volume84
Issue number4
DOIs
StatePublished - Feb 21 2012

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