Instruction Manual Design and Illustration
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2.4 Mechanism
A silicon-based thin film microheater is used as a rapid heating component, and a microfluidic
chip is used as a carrier for the PCR reaction. The PCR reaction system uses a fluorescent probe as an
indication of the reaction signal. As the PCR reaction progressed, the fluorescence of the positive
reaction will accumulate, and the signal is collected as images by a CMOS camera. Finally, the control
system completes data collection and makes digital image processing.
2.4.1 Control Systems
：
Embedded Control Systems
2.4.2 Temperature Control
：
Based on Joule heating principle, a silicon thin film micro-heater with
metal coating is used as a heating element, which has high thermal conductivity and good
temperature-resistance linear curve, thereby achieving rapid and accurate temperature rise. In addition,
the cooling system is equipped with a high-speed and small fan and an optimized duct was designed to
effectively increase the cooling rate.
2.4.3 Reaction Carrier
：
The silicon-based microfluidic chip can be used as a disposable carrier for the
PCR reaction. The internal reaction chamber has a volume of 2 μL. The silicon substrate is tightly
contacted with the thin film micro-heater, which is beneficial to improve heat transfer efficiency and
temperature uniformity. Covering the silicon substrate with a glass wafer to form a PCR reaction
chamber can effectively avoid sample contamination.
2.4.4 Fluorescence signal detection: The reaction system of PCR utilize a fluorescent probe or a
general dye as an indication of the signal. As the PCR reaction proceeds, the fluorescence of the
positive reaction will accumulate and the signal is collected as images by the CMOS camera. At last,
the control system completes data collection and processing.