Studies On Fabrication And Sample Introduction Techniques For Microfluidic Chips

Chip-based microfluidic systems have attracted broad interest in recent years as a major form for realizing the lab-on-a-chip, or uTAS concept, which aims to perform sample introduction, pretreatment, reaction, separation and detection operating all in single chip. The present work was focused on developing novel fabrication and sample introduction techniques for microfluidic chips. The fabrication for microchips is the base and precondition for studies on microfluidic chips. The current studies on sample introduction for microfluidic chips are relative weak and should be improved.In the first chapter, the developments on fabriaction and sample introduction techniques for microfluidic chips were reviewed.In the second chapter, a simple and novel bonding process at room & low temperature(80—100 ℃) was developed for the fabrication of galss microfluidic chips. High quality bonding with higher than 6 kg/cm2 bonding strength was achieved under hydrolyzed layer conditions presented on the plate surfaces after soaking the substrates in acid or water for extended periods in the routine lab, without the requirement of clean room facilities, or special facilities such as programmed high-temperature furnaces. This bonding process features simple operation, good smoothness of the plate surface, and high bonding yield (> 95%). Microfluidic chips bonded by this process was applied in chip-based capillary electrophoresis (CE) system for separation of amino acids.In the third chapter, a continuous sample introduction system featuring falling-drop interface for chip-based CE systems was developed. The falling-drop design allowed electrical isolation of the CE chip from the sample introduction system. Two falling-drop interface designs were employed and the operating conditions were optimized. The falling-drop interfaces were applied to perform continuous sample introduction and chip-based CE for amino acids.In the fourth chapter, a microfluidic chip-based CE system with integrated sample introduction system was developed. A diffuser/nozzle valveless micropump was integrated with the CE chip for the first time, served as driving source for sampleintroduction on chip. The operating conditions for micropump and sample introduction system were optimized. The present integrated system was applied in CE separation for amino acids to demonstrate the performance.