Abstract
This study has successfully used LTPS TFT process technology to design a bio chip that can perform dielectrophoretic (DEP) manipulation and optical detection. The LTPS process has the benefit of less post-processing steps required than the CMOS (complementary metal oxide semiconductor) process to realize the chip. In addition, the process can provide a large chip area at low cost. Reliability, however, is the main issue that the LTPS process has to improve. The basic principle of DEP force and its mathematical model will be presented. CFD-RC software is utilized for simulation to ensure microbeads can be successfully moved to the target electrodes based on our design. Bio-detection is achieved by using image sensors. H-spice simulation is used to verify the feasibility of the circuit design. In the experiments, a thin layer of silicon dioxide is deposited on chip surface for surface functionalization and biomolecule immobilization. Immobilized microbeads can be moved to the target microelectrodes by DEP and produce specific bindings with the immobilized biomolecules on sensor surface. Those beads are successfully detected by the optical sensors underneath microelectrodes to validate the bio-recognition event.