| My research interests and experiences have focused on Bio-analytical System-On-Chip, which would perform detection/sensing, cell sorting, isolating, sample preparation and analysis in a micro/nano-integrated manner for early cancer diagnosis and tumor stem cells research. As far, I believe I have made contributions in following research topics:; Integrated microfluidic-biophotonics system. I have made contributions on integrating micro-optic and photonic devices with microfluidic systems. More specifically speaking, micro-mirrors and waveguides are monolithically integrated with microfluidic channels in various configurations. Each configuration requires different process techniques and applies to different situations. The first functional device I have demonstrated is the on-chip flow cytometer. It provides the on-chip fluorescent excitation/detection and time-of-flight measurement. Photonic integrated circuits (PIC) provide a low-cost and compact solution that is superior to conventional free-space optics and microscopy. One example I have demonstrated is that, instead of improving the hardware such as more advanced lasers and more sensitive detectors (PMT), superior sensitivity enhancement of optical detection can be achieved by multi-sampling and cross-correlation analysis executed by the waveguide-array. In addition to increasing the sensitivity, the waveguide-array technique also achieved a great enhancement of signal distinction.; Micro/nano manipulation. With the small dimensions of microfluidic systems, large electrical field strengths can be obtained with small voltages. I showed an example how the microfluidic channel, waveguides and electrodes can be brought to a compact integration. This particular device utilizes the dielectrophoretic (DEP) field to trap and rotate single cell for detail optical interrogation. Dielectrophoretic field can be applied to regulate the particles by the trailing electrodes along the microfluidic channels. Deploying the electrode-railroad allows more flexible and compact design of microfluidic channel systems than controlling the laminar sheath flow in microfluidic channels.; I demonstrated a micro-mixer utilizing near-field acoustics. Actuated by miniaturized piezoelectric actuator, the device was made of soft polymeric material in order to slow down the speed of acoustic wave. Thus, the acoustic wavelength can be effectively scaled down to millimeter/centimeter range without operating the actuator in ultrasound frequency range, which requires bulky transducer and high-frequency function generator. The motion of suspended micro-particles in response to acoustic wave is correlated to the frequency. |
