Influence of Nanometric Holes on the Sensitivity of a Waveguide-Mode Sensor: Label-Free Nanosensor for the Analysis of RNA Aptamer−Ligand Interactions

Evanescent-field-coupled (EFC) waveguide-mode sensors can be used to detect nucleic acids or proteins from the changes in the local index of refraction upon adsorption of the target molecule on a waveguide surface. We recently described an EFC waveguide-mode sensor in which nanometric holes on a wav...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2008-09, Vol.80 (17), p.6602-6609
Main Authors: Gopinath, Subash C. B, Awazu, Koichi, Fujimaki, Makoto, Sugimoto, Katsuaki, Ohki, Yoshimichi, Komatsubara, Tetsuro, Tominaga, Junji, Gupta, Kailash C, Kumar, Penmetcha K. R
Format: Article
Language:English
Subjects:
Adsorption
Analytical chemistry
Aptamers, Nucleotide - analysis
Aptamers, Nucleotide - metabolism
Biosensing Techniques - methods
Biotin - metabolism
Chemistry
Exact sciences and technology
General, instrumentation
Ligands
Molecules
Nanoscience
Nanotechnology - instrumentation
Nanotechnology - methods
Protein Binding
RNA-protein interactions
Sensitivity and Specificity
Staining and Labeling
Streptavidin - metabolism
Studies
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Summary:Evanescent-field-coupled (EFC) waveguide-mode sensors can be used to detect nucleic acids or proteins from the changes in the local index of refraction upon adsorption of the target molecule on a waveguide surface. We recently described an EFC waveguide-mode sensor in which nanometric holes on a waveguide film resulted in an improved sensitivity in the analysis of the interactions of biomolecules. In the present study, we have shown that sensitivity depends upon the diameter of the holes, where increase in diameter of holes increases spectral shift resulting in an improved sensitivity. Using this improved EFC waveguide-mode sensor, we could detect interactions between RNA and a small ligand, cyanocobalamin (vitamin B12), and between RNA and a protein (human coagulation factor IXa). These two interactions were monitored on surfaces modified with biotin−streptavidin−biotin and N-(2-trifluoroethanesulfonatoethyl)-N-(methyl)triethoxysilylpropyl-3-amine, respectively.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac800767s