Views: 0 Author: Site Editor Publish Time: 2021-11-08 Origin: Site
PCR machine, also known as PCR gene amplification instrument, PCR amplification instrument, polymerase chain reaction nucleic acid amplification instrument, is an instrument that amplifies specific DNA using PCR (Polymerase chain reaction) technology. PCR machine is widely used in medical and biological laboratories, such as for determining whether a test body will exhibit PCR machines are widely used in medical and biological laboratories, for example, to determine whether a test organism exhibits a genetic disease profile, to diagnose infectious diseases, to replicate genes, and to identify parentage. What is a PCR machine?
Here is the content list:
l The basic structure of a PCR machine
l Working principle of PCR machine
l Reaction kinetics of the PCR machines
A PCR machine usually consists of a hot cover part, a thermal cycle part, a transmission part, a control part, and a power supply part, etc.
The working principle of the PCR machine is similar to the natural replication process of DNA, whose specificity depends on oligonucleotide primers complementary to both ends of the target sequence, and consists of three basic reaction steps: denaturation-annealing-extension.
1. Denaturation of template DNA
The template DNA is heated to about 93°C for a certain time to dissociate the double-stranded template DNA or the double-stranded DNA formed by a PCR machine to make it single-stranded so that it can bind to the primers in preparation for the next round of reaction.
2. Annealing (denaturation) of template DNA and primers
After the template DNA is denatured into single-stranded by heating, the temperature is lowered to about 55°C and the primers are paired and bound to the single-stranded complementary sequence of the template DNA.
3. Extension of primers
The DNA template-primer conjugate is synthesized under the action of TaqDNA polymerase, using dNTP as the reaction material and the target sequence as the template, to synthesize a new semi-conserved replicated strand complementary to the template DNA strand according to the principle of base-pairing and semi-conserved replication.
By repeating the denaturation-annealing-extension process, more "semi-conserved replicate chains" can be obtained, and these new chains can be used as templates for the next cycle.
The PCR machine takes 2~4 minutes to complete each cycle, and so on repeatedly, the DNA produced in each cycle can become the template for the next cycle, and each cycle amplifies the copy number of DNA specific region between two synthetic primers by 1-fold, and the PCR machine product amplifies rapidly in the exponential form of 2. After 25~30 cycles (2~3 hours), the PCR machine can theoretically amplify the gene more than 109-fold after 25~30 rounds (2~3 hours), and in practice, it can generally reach 106~107-fold.
The three reaction steps of the PCR machine are repeated, resulting in an exponential increase in the amount of DNA amplification. The final DNA amplification of the reaction can be calculated using y=(1+X) n. Y represents the number of copies of the DNA fragment amplified, X represents the average amplification efficiency per amplification, and n represents the number of cycles. The theoretical value of the average amplification efficiency is 100%, but in the early stage of the actual reaction, the increase of the target sequence DNA fragment is exponential, and with the gradual accumulation of PCR machine products, the amplified DNA fragment no longer increases exponentially, but enters the linear growth period or stationary period, i.e., the "stagnation effect", so that the average efficiency of the PCR machine reaches The average efficiency of the PCR machine does not reach the theoretical value.
Bioteke Corporation, which focus on molecular diagnostics and rapid detection, particularly, on nucleic acid extraction, is a professional high-tech manufacturer and PCR machines. It is set in Wuxi City, Jiangsu province, China. So, we are looking forward to cooperating with you.
