Background reduction in a young interferometer biosensor

Integrated optical Young interferometer (IOYI) biosensors are among the most sensitive label-free biosensors. Detection limits are in the range of 20 fg/mm2. The applicability of these sensors is however strongly hampered by the large background that originates from both bulk refractive index changes and non-specific binding of molecules to the sensor surface. In this contribution we demonstrate a new method that allows us to separate the bulk background from the analyte signal. We show theoretical analysis and preliminary proof-of-principle experimental data, where binding of protein A is discriminated from a bulk refractive index change induced by D-Glucose, using multiple wavelengths. We anticipate that this method will increase the general applicability of IOYI sensors.