UC Berkeley

Infectious and non-communicable diseases impose a global burden of health on both developing and developed countries despite technological advancements in medicine and healthcare. In this perspective, point-of-care testing (POCT) has been paid attention as an area with enormous potential to solve this problem. Point-of-care molecular diagnostic enables to provide diagnoses from clinical samples to clinicians without wasting time such as sample transporting or sample preprocessing. However, most of nucleic acid diagnostics still are performed in central health facilities because they need top-notch equipment and well-trained personnel. To overcome these difficulties, the emergence of microfluidics has been attracted because of its inherent features including consuming small volume of sample and reagent, precise controllability of laminar flow, short processing time for analysis, and miniaturization of devices. This dissertation is a part of effort to develop an integrated molecular diagnostic platform for improving global health care and the quality of life. Firstly, we developed a microfluidic device for sample preparation. The purpose of sample preparation is to enrich target cells, remove unnecessary cells, and lyse target cells for nucleic acid detection. The preconcentration and selective capture of cells are demonstrated in the microfluidic device by using porous materials and antibody without any external bulky equipment such as a centrifuge. Then, photonic PCR is presented as a new technology of thermal cycling. When light comes to gold (Au), Au can absorb light efficiently due to its plasmonic-assisted high optical absorption (~ 65% at 450 nm) and quickly release the light energy as a thermal energy. Using this simple principle, we demonstrate the target DNA amplification within 5 minutes on 30 cycles. In addition, a comprehensive heat transfer simulation of the photonic PCR is carried out to improve the performance of the photonic PCR. Simulation of heat transfer model demonstrates the importance of optical absorption of Au and thermal diffusivity of materials on heating and cooling ramping rates. Finally, the development of a new integrated molecular diagnostics is demonstrated for bacterial detection in urine samples.