Specific bio-recognition reactions observed with an integrated Mach-Zehnder interferometer.

The combination of an integrated Mach-Zehnder-interferometer (iMZI) at the bottom of a fluidic microchannel system with supramolecular interfacial binding layers optimized for biosensing purposes is described. The model system used is based on the highly specific interaction of streptavidin to its 'ligand' biotin: a single monolayer of a correspondingly derivatized silane-compound is formed by a self-assembly procedure on top of the channel rib guiding the light through the channels. Injection of a streptavidin solution which leads to the formation of a protein monolayer of d = 2.