Biomedical Applications for Microfluidic Devices /

My thesis research has focused on the biomedical applications of microfluidic devices, including accommodating liquid intraocular lens, wirelessly powered dielectrophoresis microfluidic platform, and evaporative microarray for molecular in-vitro diagnosis. In the first part, I developed an accommodating intraocular lens that can largely improve cataract patients' living quality by enabling patients to focus on far distance as well as near distance. Compared to natural eyes, today's commercially available accommodating IOLs produce a much limited tuning range. The large performance gap is attributed to the fundamental difference between crystalline lens and the optic-shift IOLs in the operation principles. In the thesis we designed and made a fluidic IOL that can change its curvature as the crystalline lens does. Both mechanical performance and optical quality are tested under the physiological conditions of aged eyes, promising complete restoration of vision accommodation. In the second part, I reported the first microfluidic device integrated with a printed RF circuit so that the device can be wirelessly powered by a commerciallyavailable radio -frequency identification (RFID) reader. The device eliminates the need for wire attachments and external instrument, so the operators can use the device in essentially the same manner as they do with microscope slides. The integrated circuit can be fabricated on a flexible plastic substrate at very low cost using a roll- to-roll printing method. Electrical power at 13.56 MHz transmitted by a RFID reader is inductively coupled to the printed RFIC and converted into 10V DC (direct current) output, which provides sufficient power to drive a microfluidic device to manipulate biological particles such as beads and proteins via the DC dielectrophoresis (DC-DEP) effect. In the third part, I developed a mathematical model for microarray probe/target reaction. The analysis was based on any chemical reaction between target molecules suspended in solution react and probes immobilized on a solid substrate, so it can be used to analysis hybridization efficiency in genomic microarray, as well as binding efficiency in protein microarray. The model indicated that besides diffusion, electrical repelling force between negatively charged probe and target molecules is the main cause for low hybridization efficiency. Based on the model, we further proposed a novel evaporative microarray, which can reduce the target solution thickness down to 80 [mu]m and theoretically enrich the concentration of molecules up to 1000 fold before target/probe chemical reaction. Preliminary data demonstrated the feasibility of integration of evaporation with microarray using black silicon templat