It has been 3 years since we fought the epidemic in late 2019, and during these three years, various methods have been used to detect the virus in response to the epidemic. Currently, the main nucleic acid detection methods for the new coronavirus include PCR, thermostatic amplification, sequencing, and CRISPR assays. Among them, PCR technique is the mainstream method of virus detection method, and is also the current officially recognized method for the determination of neo-coronavirus.
I. PCR method
PCR, or polymerase chain reaction, is a method for amplifying nucleic acids in the sample to be tested. The second generation PCR technology, also known as fluorescent PCR method, is based on the extension of the PCR method, which means that fluorescent substances are added to the reaction system, real-time fluorescence detection is achieved by specialized instruments, and quantitative calculations are performed on the template. It is the most commonly used method for rapid detection of new crown nucleic acid, and currently we perform rapid detection of new crown nucleic acid generally using this method. This method is very demanding in terms of temperature during the experiment, and requires real-time temperature adjustment with different processes.
Thermostatic amplification method
The thermostatic amplification method avoids the temperature adjustment of the sample implemented in the fluorescent PCR method and mainly involves 2 types of techniques, one using special enzymes to replace the high temperature unstranding step in PCR; the other involves the conversion between DNA and RNA to amplify. The constant temperature device can complete amplification and chromatography detection, which is suitable for lower tier medical institutions and for various application scenarios to achieve pathogenic RNA POCT detection.
Sequencing method
Sequencing method can directly decipher the arrangement order of nucleic acid bases, and sequencing is necessary for a completely unknown new virus. This technique was used to discover the novel virus at the beginning of the New Crown epidemic; in addition, the method can monitor in real time whether the virus mutates and how many generations it mutates by deciphering the alphabetical order. The current multiple mutated strains of New Crown were detected by this method.
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Fourth, CRISPR detection method
The full name of CRISPR is Clustered Regularly Interspaced Short Palindromic Repeats (Clustered Regularly Interspaced Short Palindromic Repeats).CRISPR/Cas system as a molecular diagnostic technology is mainly based on the system's function of specific identification and cleavage of nucleic acid sequences, which The trans-cleavage property of the cleavage function is the most important function for the CRISPR/Cas system to exert its in vitro diagnostic capability. The three Cas proteins (Cas12, Cas13 and Cas14) with trans cleavage activity are activated to cleave non-target nucleic acids, further amplifying the detection signal and improving detection sensitivity, while the specific recognition of target sequences by gRNA further improves detection specificity, making the CRISPR/Cas diagnostic system highly sensitive and specific The detection technology of CRISPR is a new neo-coronavirus RNA assay, which requires only purified nucleic acid molecular samples and can be completed in one hour time by three simple steps. Currently, it is not very common.
Among the above four rapid nucleic acid detection methods, PCR is the least expensive, more convenient and more accurate method, which is why it is still the "gold standard" for diagnosing neoplastic patients. But now, through technical innovation, the manufacturer has developed the "New Coronavirus Rapid Test System" equipped with efficient detection reagents and portable amplification instrument, which can improve the efficiency of nucleic acid detection without changing the accuracy and help for epidemic prevention and control. The system is capable of improving the efficiency of nucleic acid detection without altering the accuracy, thus contributing to epidemic control.
