Design and development of a lab-on-chip for biomedical analysis based on electrowetting on dielectric technique

The purpose of this thesis research project has been the development of a compact and versatile optoelectronic platform able to implement all the functionalities needed for a lab-on-chip operation. The project includes also the development of the electronics needed for the control of the system. In particular, the proposed platform includes three different modules designed for the fluid handling through the ElectroWetting On Dielectric (EWOD) technique, the thermal sample treatment and optical detection. These modules incorporate thin film microelectronic devices (such as photosensors and interferential filters for the optical detection, or heaters and temperature sensors for the sample treatments) on glass substrates connected to the electronic microcontrollers. Moreover, the use of handling techniques which avoid the use of pumps and syringes led to a portable, high-sensitive and low-power consumption lab-on-chip device. All of the modules have been designed, fabricated and tested separately. Finally, a device integrating all of the functionalities mentioned before has been designed for the development of a multifunctional platform able to perform a “true” lab-on-chip biomolecular system

Integration of amorphous silicon photosensors with thin film interferential filter for biomolecule detection

This work presents a thin film device, combining, on the same glass substrate, photosensors and long-pass interferential filter to achieve a compact and efficient sensor for biomolecule detection. The photosensors are amorphous silicon stacked structures, while the interferential filter is fabricated alternating layers of silicon dioxide and titanium dioxide, directly grown over the photosensors. The system has been optimized to effectively detect the natural fluorescence of Ochratoxin A, a highly toxic mycotoxin present in different food commodities. In particular, the long-pass interferential filter has been designed to reject the wavelengths arising from the excitation source (centered at 330nm) thus transmitting the OTA emission spectrum (centered at 470nm). Experimental results show that the filter strongly reduces the photosensors quantum efficiency below 420nm, while keeps it nearly constant at higher wavelength