Influence of nanometric holes on the sensitivity of a waveguide-mode sensor: Label-free nanosensor for the analysis of RNA aptamer-ligand interactions

Subash C B Gopinath, Koichi Awazu, Makoto Fujimaki, Katsuaki Sugimoto, Yoshimichi Ohki, Tetsuro Komatsubara, Junji Tominaga, Kailash C. Gupta, Penmetcha K R Kumar

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    Abstract

    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-streptavidinbiotin and N-(2- trifluoroethanesulfonatoethyl)-N-(methyl)triethoxysilylpropyl-3-amine, respectively.

    Original languageEnglish
    Pages (from-to)6602-6609
    Number of pages8
    JournalAnalytical Chemistry
    Volume80
    Issue number17
    DOIs
    Publication statusPublished - 2008 Sep 1

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    ASJC Scopus subject areas

    • Analytical Chemistry

    Cite this

    Gopinath, S. C. B., Awazu, K., Fujimaki, M., Sugimoto, K., Ohki, Y., Komatsubara, T., Tominaga, J., Gupta, K. C., & Kumar, P. K. R. (2008). Influence of nanometric holes on the sensitivity of a waveguide-mode sensor: Label-free nanosensor for the analysis of RNA aptamer-ligand interactions. Analytical Chemistry, 80(17), 6602-6609. https://doi.org/10.1021/ac800767s