At the end of the 20th century, Vogelstein et al. proposed the concept of digital PCR (digital PCR, dPCR), by dividing a sample into tens to tens of thousands of copies and assigning them to different reaction units, each unit contains at least one copy of the target molecule (DNA template). In each reaction unit, the target molecule is amplified by PCR, and after the amplification is completed, the fluorescent signal of each reaction unit is statistically analyzed.
Digital PCR is an absolute quantification technology of nucleic acid molecules, which mainly adopts microfluidic or dropletization methods in the current popular research field of analytical chemistry. Digital PCR generally includes two parts, namely PCR amplification and fluorescence quantitative analysis. In the PCR amplification stage, unlike traditional techniques, dPCR generally requires the sample to be diluted to a single molecule level and distributed evenly to tens of thousands of reaction chambers. This is equivalent to enriching the target gene in disguised form. At the same time, due to the large dilution of the original sample, the concentration of PCR inhibitors was significantly reduced, so that the requirements of dPCR for the inhibitors in the initial PCR reaction were significantly lower than that of qPCR (Quantitative Real-time PCR). Different from the method of qPCR for real-time fluorescence measurement of each cycle, dPCR technology collects the fluorescence signal of each reaction unit after the amplification is completed. The droplet with fluorescent signal is interpreted as 1, and the droplet without fluorescent signal is interpreted as 0, and finally the initial copy number or concentration of the target molecule is obtained according to the principle of Poisson distribution and the number and proportion of positive droplets.。
Basic Principles of Picture Digital PCR
CoreMorrow's Piezo Actuator
Piezo Stack
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Piezo Nanopositioning Stage
Piezo Objective Lens Positioner/ Piezo objective Scanners
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