We have achieved the design, fabrication and packaging of microfluidic networks with photonic sensors for novel labon- chip platforms which incorporate the on-chip biosensing detection. As sensors, we used an integrated Mach-Zehnder interferometer (MZI) based on TIR waveguides (Si/SiO2/Si3N4) of micro/nanodimensions for evanescent field detection of biomolecular interactions onto the sensing areas. For the lab-on-a-chip development, the biosensors have been integrated with a 3D microfluidic polymer network. In addition, we have developed a novel hybrid device for coupling light into the waveguides of the Mach-Zehnder sensor. The coupling hybrid device is composed of a thin film of diffraction gratings fixed to a polydimethylsiloxane film. The optical characterization has shown the excellent compatibility and integration between fabrication technologies of silicon MZI, SU-8 polymer microfluidic network and mountable grating couplers.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.