Design And Fabrication Of A PCR Biochip Based On MEMS

DNA PCR amplification is bioreaction for DNA analysis. It expands a little to a large amount of DNA molecule. Reviewing the research on the PCR biochip, one monolithically integrated was designed and fabricated in a substrate based on MEMS technology. DNA reaction chamber, microchannel, temperature sensor and heater are integrated on the PCR biochip. The chip PCR is realized with the material of silicon with the size of 8mm ×4mm ×0.3mm. The volume of chamber is roughly 2 micro liters with the size of 4mm×2mm×0.3mm.The bottom of chamber is constructed by the film of Si3N4 with the thickness of 2 micrometers. The platinum heater and temperature sensor are deposited on the Si3N4 film. With the PCR biochip, a miniaturized analyzing system can be realized for PCR, and it can be very expediently applied to the medical, environment analysis in outdoor. Matching with the PCR biochip, a miniaturized heat cycler system is designed and fabricated with proper hardware and software.The design of the hardware is based on the principle of reducing the dimensions, lowering the power consumption, fabricating a pocketable instrument. The software is a key part for accurately control the temperature and easy operation etc. In the paper, PCR biochips with different structrues were designed and researched in the respects of its physical characteristics including thermal transfer of the heater, the temperature field distribution etc. A standard Hepatitis B (HB) testing reagent was used as thermal cycling materials for DNA amplification with the PCR biochip. The experiment employed the fluorescent dye S YBR Green I assay technique so that a fluorescent can be detected. The test has been completed with enhanced fluorescence result when 30 cycles finished on the PCR biochip. The PCR biochip's characteristic is as follows: 1.chamber capacity :<2 μl. 2. heating rate 15℃/s. 3.cooling rate 10 ℃/s. 4. temperature accuracy ≤0.4 ℃. 5. power consumption <800 mW.