Studies and applications of microfluidics and microsystems for cell biology and molecular detection

Abstract

In this thesis, we mainly studied and applied microfluidics and its related microsystems in the biological research field, including cell study and biomolecule detection. In chapter 1, we mainly make an introduction to the concept of microfluidics, such as physics in microscale level and materials used in microfluidics chip fabrication. Then we made a simple description of microchip-based PCR, which is a very important application of microfluidics. This includes PCR chip types, temperature control strategy and PCR result detection methods. Afterward, some other application based on microsystems was stated, such as mechanobiology, cell patterning and digital PCR. In chapter 2, we designed a magnetic micropillar array for based on microfabrication technology to deliver a homogeneous force to cell cultured on. We found that cell proliferation and death has relationship with the frequency of the applied force. In chapter 3, we first designed a stencil by which cell patterning work could be realized in a digitally programmable way. For demonstration, we successfully pattern proteins and cells to form a “HKUST” pattern. In chapter 4, we designed an integrated portable microchip based real time PCR machine for point of care need. In our design, we chose silicon for chip fabrication and developed a user-friendly strategy for sample loading and sealing based on capillary action. we could successfully detect the target DNA at the concentration as low as 5 fM. We chose Si-based microheater as the heating element which could realize a very fast heating and cooling speed and significantly decrease the reaction time. What’s more, Si based microheater and PCR microchip could be produced in semiconductor foundry and the cost could be dramatically lowered. In chapter 5, we designed a new type of digital PCR chip by adopting silicon as the main fabrication material, which we called Si based passive power dPCR chip (SiPPC). We found that, by fabrication the dPCR reaction chambers on silicon, the water evaporation is independent of the size scale down of the chamber. It means that the dPCR reaction pixel could be easily smaller with a good water evaporation control and without complex anti-evaporation process.

Date of Award	2016
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology