Optimization of silica surface with nanosize holes for immobilization of biomolecules and analysis of their interactions.

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.