Highly sensitive integrated optical biosensing platform based on an asymmetric Mach-Zehnder interferometer and material-selective (bio)functionalization

An innovative integrated optical biosensing platform with an extremely high sensitivity is presented. The platform uses TriPleX (Si3N4/SiO2) waveguide technology in an asymmetric Mach-Zehnder Interferometer (aMZI) configuration, which is intrinsically more sensitive than other waveguide-based sensor technologies and Surface Plasmon Resonance (SPR). The performance of the sensor is enhanced by material-selective functionalization of Si3N4 vs. SiO2, allowing site-selective immobilization of the bioreceptor to the waveguide surface. The rest of the chip surface is modified with an antifouling layer to reduce non-specific adsorption. Analyte binding is thus confined to the waveguide surface, which results in improved sensitivity and limit of detection