Design And Fabrication Of Microfluidic Diagnostic Systems

The area of micro total analysis systems, also called "lab on a chip", or miniaturized analysis systems, is growing rapidly, especially in the field of clinical diagnostics. The principale advandages associated with u-TAS include saving time and cost, several analyses can be completed simultaneously and automatically.The micro total analysis systems are based on the microfluidics intergrated chemical processing and analysis. Though still in many ways in its infancy, interest in this field has grown explosively over the last decades. Typical micro total analysis systems used for clinical diagnostics are often composed of three parts: sample preparation; chemical amplification and detection (including electrophoresis and hybridization). This dissertation mainly focuses on studying these three parts.1. Two types of DNA purification chips based on the method of SPE (solid phase extraction) have been fabricated and studied. One was fabricated by silicon using MEMS (micro-electro mechanical system) technology; the other was fabricated by PDMS (polydemethylsiloxane) through soft lithography, using magnetic beads to purify DNA. Both chips were used to purify the DNA from PCR products. The silicon chip was also used to purify DNA from Yeast bacteria.2. Biological experiments have been conducted to test the PCR chip and a fluorescent method has been, developed3. An immuno chip was fabricated by PDMS using soft lithography. Methods were developed to immobilize human IgG on the surface of magenetic beads. The immuno reaction was successfully performed between the human IgG immobilizaed on the magnetic beads and FITC labeled sheep anti human IgG in the channel.4. PDMS-glass microchip used for performing DNA hybridization reaction.has been fabricated and studied. Biotin -avitin system (BAS) was used to immobilize DNA on the PDMS channel compared to the direct immobilization methds. The hybridization reaction also has been examined between immobilized probe and target DNA.