How to correctly select a disposable virus sampling tube?

        With the ravage of delta, a large-scale nucleic acid test has been started in China. However, only the complete collection and non-destructive preservation of samples in large-scale nucleic acid test can enable the tester to make an accurate judgment on the infection of novel coronavirus in the person to whom the sample belongs. How to collect and preserve samples intact?

         How to correctly select a disposable virus sampling tube? Pay attention to the following aspects:

1. Swab

   flocking swab, as a sample collection tool, has the advantages of high sample collection rate, good adsorption and not easy to shed wool, which is not available in cotton swabs, and can collect samples well.

2. Virus storage tube

   general name of virus sampling tube disposable virus sampling tube is generally used for the detection and sampling of infectious pathogenic microorganisms by disease control departments and clinical departments. It is applicable to the detection and sampling of influenza virus (including general influenza, highly pathogenic virus, influenza A (H1N1), hand, foot and mouth virus, novel coronavirus, measles, rubella and other types of viruses. VTM virus sampling tube can also be used for detection and sampling of mycoplasma, chlamydia and Ureaplasma urealyticum.

        Generally,  the virus sampling tube is equipped with a disposable flocking swab. From the appearance, the flocking swab is white and soft. Using this soft brush during the sampling process will make the user feel no foreign matter, and it is suitable for people sampling at different parts. Moreover, the flocking swab is designed with a break point that conforms to the length of the sampling tube and the natural lumen of the human body, which is not only convenient for sampling but also convenient for specimen transportation.

      The virus sampling tubes are filled with infectious substances, and some are even highly pathogenic substances. Therefore, the requirements for packaging containers are very strict, and the requirements in three aspects should be met at the same time:

 (1) safety of transportation.

Ensure no leakage of samples during transportation. Sampling tubes complying with who regulations and biosafety regulations.

 (2) security of storage.

  ensure that the sample does not leak during storage. Sampling tubes complying with who regulations and biosafety regulations.

(3) . validity of samples.

       Ensure that the sampling tube itself will not have toxic effect on the sample.

  3. Virus preservation solution

   as the core of the sampling tube, virus preservation solution can be divided into two types, i.e. inactivation type and inactivation type. Inactivated preservation solution needs to ensure the safety of laboratory personnel and prevent the second spread of virus; In addition to the above-mentioned characteristics, the preservation solution of keeping alive also needs to have the characteristics of being able to store for a long time in a wide temperature range, and the virus nucleic acid is not easy to be degraded, so as to maintain the biological characteristics of the virus to the maximum extent.

4. Packing form:

   in terms of packaging form, Shenzhen medico Biomedical Technology Co., Ltd. makes use of its own advantages to fill the preservation solution in the clean workshop meeting GMP standards, and uses disposable easy to tear packaging to avoid pollution and improve product quality and performance. Before the products leave the factory, irradiation sterilization is also carried out to ensure that the ex factory products will not cause pollution to the samples and avoid affecting the final test.

Experimental study on inactivation of disposable virus sampling tube

Virus sampling tube:

Disposable virus sampling tube (inactivated type)

Experimental materials:

Lentivirus (gkai gene, gcnl0319432), HEK293T cells

Nucleic acid extraction kit and extractor:

（BNP027-2B, M32)

Xinguan sampling tube：

Experimental method:

Refer to the detection method described in the virus inactivation test in the technical specification for disinfection (2002 Edition) to determine the inactivation capacity of the virus preservation tube.

Step 1: cell culture

HEK293T cells in good growth state were digested and counted, and diluted with 1 × 104 / ml, according to 100 μ L / well volume, make three multiple wells for each gradient of virus, calculate the required number of inoculation wells, and slowly and evenly inoculate the cells into 96 well plates. Put it into a 5% CO2 incubator at 37 ° C and incubate overnight

Step 2: lentivirus dilution

The lentivirus with a titer of 107-108tu / ml was diluted by 10 fold gradient, and three gradients were continuously diluted.

Step 3: virus inactivation

Place the diluted virus at room temperature, mix it with the inactivated virus preservation solution (batch number: 220201 / 220207 / 220211) in a volume ratio of 1:1, and place it at room temperature for 1min, 5min and 10min respectively for inactivation.

Step 4: stop inactivation

The virus isolation medium (which can be replaced by DMEM complete medium) was diluted 1000 times to neutralize the inactivation preservation solution and terminate the inactivation.

Negative control: the mixture of virus isolation medium and inactivated virus preservation solution diluted 1000 times;

Positive control: the mixed solution of virus isolation medium diluted 1000 times of virus original solution.

Step 5: virus incubation

The cell culture medium was aspirated from the previously cultured HEK293T cells, and 100 μ L of the prepared virus mixture, and the corresponding positive control and negative control. The virus was incubated for 3 hours, and was removed from the incubator and shaken every 30 minutes.

Step 6: cell culture

After the incubation, the virus solution was aspirated, and 100 μ L DMEM complete medium, place 96 well plates in a 5% CO2 incubator at 37 ° C, and observe the cell state.

Step 7: observation and counting of fluorescent cells

Continue to culture for 48-72h, and observe the cell state during the period. If the cell culture solution turns yellow, change the solution, count the wells with the appropriate number of fluorescent cells, and calculate the virus titer.

experimental result：

Experimental conclusion:

It can be seen from the data in Fig. 1 and table 1 that after lentivirus was inactivated for 1min, 5min and 10min, HEK293T cells grew normally under the microscope bright field; Three batches of inactivated virus storage tubes can effectively inactivate the virus after interacting with the virus for 5min.