The PCR machine uses heating to denature the DNA, and uses restriction enzymes to melt the DNA double-strands. Under the action of the polymerase, the single-strands are copied into double-strands to achieve the purpose of gene replication. According to the purpose of DNA amplification and detection standards, PCR machines can be divided into four types, namely ordinary PCR machines, gradient PCR machines, in-situ PCR machines, and real-time fluorescent quantitative PCR machines.
 
The primers added during PCR amplification are labeled with fluorescein, so that the primers and fluorescent probes are specifically combined with the template at the same time. The amplification results are collected in real time by the fluorescence signal acquisition system and sent to the computer analysis and processing system, and the quantitative results are output in real time. Such a PCR machine is called a real-time fluorescent quantitative PCR machine.
 
Types of real-time fluorescent quantitative PCR machine
1. Metal plate real-time quantitative PCR machine
It can be used as an ordinary PCR instrument, with gradient function, large sample volume, no special consumables, poor temperature uniformity, edge effects, and the reaction conditions of the standard curve are difficult to be completely consistent with the sample.
2. Centrifugal real-time quantitative PCR machine
The temperature uniformity is good. The same excitation light source and detector are used to detect samples rotating to the front at any time, which effectively reduces system errors, but it can only accommodate a small amount of samples, and some require special capillary tubes as sample tubes, which increases the cost of use, and it has no gradient function.
3. Quantitative PCR machine with independent temperature control for each well
Different sample tanks have independent intelligent heating and cooling modules, and the temperature of each well is independently controlled, which is suitable for rapid detection of multiple indicators.
 
Features of real-time fluorescent quantitative PCR machine
1. Strong specificity: the "double insurance" of primers and probes can avoid false positives in detection.
2. High sensitivity: Analyze the logarithmic phase of PCR products, and collect fluorescent signals by automatic instrument, which avoids human interference factors.
3. Avoid contamination: fully enclosed reaction, no post-PCR processing required.
4. Realization of quantification: use standard products to obtain a standard curve, and combine with Ct value for accurate quantification.
5. High efficiency and low consumption: one tube and multiple inspections can be realized.
6. Simple operation: online real-time monitoring of amplification results, no need to contact harmful substances.
7. Fast: Response time <1.5 hours.