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Abstract: We have previously made several modifications to the sensing chips of waveguide-mode sensors to permit detection of the interactions of several biomolecules at the 50-nM level. We further improved the sensitivity of this sensor by preparing a complex of a colored material with the target biomolecule. By using this strategy, we achieved a detection limit equivalent to 1nM for the interactions of aptamers with proteins in the presence of Coomassie Brilliant Blue; this corresponds to an approximately fiftyfold increase in sensitivity. For comparison, we also evaluated the sensitivity of our system to another fluorescent dye, Hoechst 33258. These studies delineated the suitability of our color-sensitive sensor chips for the detection of interactions of biomolecules at low concentrations. [Copyright &y& Elsevier]

Abstract: An evanescent-field-coupled waveguide-mode sensor of the Kretschmann configuration with a silica waveguide having nanoscale holes is an ideal tool for detection of bimolecular reactions. In the present research, an optimized surface of the sensor with cylindrical nanoscale holes was modified with sodium (1-{[6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoyl]oxy}-2,5-dioxopyrrolidine-3-sulfonate) (Sulfo-EMCS) to facilitate the attachment of biomolecules; the resulting surface could be cleaned for reuse simply by changing the pH of the buffering solution. The modification is expected to be useful for wide range of molecular detection. [ABSTRACT FROM AUTHOR]