Comparison of two VTM: inactivated and non-inactivated
VTM(virus transportation media）is used for the collection, preservation , transportation of common virus samples, such as corona virus, influenza viruses, HFMD virus,etc. It is a kind of liquid that protects the detected substance of the virus which are collected from throat, Nasal swabs or other specific parts, the stored samples can be used for subsequent clinical experiments such as nucleic acid extraction or purification. Usually divided into two types, one is a non-inactivated type, which can protect the protein and nucleic acid of the virus, and the other is an inactivated type, which usually contains a lysis salt that inactivates the virus, which cleavages the protein and protects the nucleic acid. The two have their own differences features and different application directions.
1. Inactivated virus preservation solution:
Nucleic acid is a biological macromolecular compound formed by the polymerization of many nucleotides, including deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is one of the most basic substances of life. The virus has a single structure and contains only one type of nucleic acid and protein. Therefore, the virus is detected when the nucleic acid is detected. Viruses are parasitic organisms and cannot survive outside the body after sampling. If they cannot be detected in time, they need to be placed in the virus preservation solution. In order to protect the safety of the virus detection environment, it is necessary to add lysis salt to inactivate the virus and release the nucleic acid that can be detected.
Inactivated virus preservation solution is mainly a virus lysis preservation solution modified from nucleic acid extraction lysis solution, which is added with a high concentration of lysis salt, which can quickly and efficiently deactivate the virus protein of the sample to be tested, which can effectively prevent the operator The secondary infection, which also contains Rnase enzyme inhibitor, can protect the viral nucleic acid from being degraded. The main purpose of the Tris, lysis salt, EDTA, etc. contained in it is to cleave the nucleic acid and release the nucleic acid, which can be carried out by subsequent real-time fluorescent RT-PCR Nucleic acid testing is used to determine whether the sample contains virus-featured nucleic acid, that is, whether it is infected with the virus. The inactivated storage solution can be stored at room temperature for a relatively long time, saving the cost of virus sample storage and transportation.
Features of inactivated virus preservation solution products:
1. Simple operation and use, no need to prepare liquid, the system contains high-efficiency virus lysate, the virus is inactivated immediately after sampling, effectively preventing the risk of secondary infection, and ensuring the safety of transportation and testing personnel;
2. Viral DNA/RNA can be stored and transported at room temperature for 1 week without degradation. After extraction according to most commercial kits, the DNA/RNA obtained is of good quality and high yield, and can complete various genetic testing and analysis experiments. Such as PCR, qPCR, etc., while saving transportation costs;
3. Contains RNase inhibitors to maximize the protection of viral nucleic acid from being degraded and greatly improve the efficiency of nucleic acid extraction.
4. It is suitable for the collection, preservation and transportation of common virus samples such as new coronavirus, influenza virus, hand, foot and mouth virus. It can collect throat swabs and nasal swabs or tissue samples of specific parts. The stored samples can be used for subsequent clinical trials such as nucleic acid extraction or purification.
2. Non-inactivated virus preservation solution:
The non-inactivated virus preservation solution does not contain lysis salt, but the preserved virus has better integrity and a higher detection rate. It is mainly based on the improved virus maintenance solution preservation solution based on the delivery medium. In addition to nucleic acid detection, it Can be used for other research. This one retains the protein coat of the virus and the DNA or RNA of the viral nucleic acid at the same time, so that the virus has the integrity of the protein epitope and nucleic acid in vitro. Of course, there is a certain risk of infectivity when operating errors. Its ingredients usually contain Hanks liquid base, gentamicin, fungal antibiotics, BSA(V), cryoprotectants, biological buffers and amino acids, etc., which protect the virus protein shell from being easily decomposed and maintain the originality of the virus sample to the greatest extent. Long-term storage after sampling needs to keep strictly low temperature.
Features of non-inactivated virus preservation solution products:
1. Low-temperature non-frozen storage does not damage the outer shell of the virus and is convenient for long-distance transportation.
2. Suitable for all kinds of swab samples, including oral swabs, nasal swabs, throat swabs, etc.
3. It can be used for H1N1 influenza virus and any other viruses that can be sampled with swabs.
4. The viral nucleic acid can be extracted with column virus DNAout or column virus RNAout.
5. Antibiotics in the sampling solution can effectively prevent bacterial and fungal contamination.
6. The sample solution is added with bovine serum albumin, which can protect the virus sample and improve the separation rate.
It can be seen from the comparison of the two that the purpose of the non-inactivated design is to preserve the integrity of the viral protein, and its composition is more complex than the inactivated type, and the cost is slightly higher. As for the increased risk of infection, there is no need to worry. As long as the institutions that can do viral nucleic acid testing are formal and operating as required, there is no danger, and there has been no case of virus infection caused by the virus storage solution by the inspector.
The non-inactivated virus preservation solution has higher requirements for the experiment, and its sensitivity should be higher, and there are more applications. After all, the preservation solution is added to the virus swab sampling tube for virus detection services, and cannot be due to its infectivity. Just deny it, the real control risk should lie in sampling and testing operations.
Post time: Jun-09-2021