New Tech’s fully automatic nucleic acid extraction and detection machine

Five strength :
● Instrument configured with the nucleic acid extraction and purified step
● Instrument configured with ultrasonic extraction module
● Instrument configured with fully automatic
● Instrument configured with variable temperature amplification
● Instrument configured with fully enclosed reagent kit

1.Do nucleic acid detection reagents need to be extracted and purifified?
The principle of nucleic acid detection is as follows:under the action of primer, DNA polymerase is used to perform chain reaction amplification on template DNA/RNA (requiring reverse transcription of NA), and then the amount of fluorescent signal released is detected to determine whether the sample contains the nucleic acid (DNA/RNA) of the pathogen to be detected.

1)Samples that have not been extracted or purified may contain many components that affect the final result: nuclease (which can dissolve the target nucleic acid and cause false negative ), protease (which can reduce DNA polymerase and cause false negative), heavy metal salt (which leads to the inactivation of synthase and causes false positive ), too acidic or too alkaline PH (which may cause the reaction to fail), Incomplete RNA (leading to false negative reverse transcription failure).

2)Some samples are difficult to amplify directly: Gram-positive and some parasites, because of their thick cell walls and other structures, if they do not go through the nucleic acid extraction and purification process, the extraction-free kit may fail for such samples.

Therefore, it is recommended to select the test kit or instrument confifigured with the nucleic acid extraction step.

2. Chemical extraction or physical ultrasonic fragmentation extraction?
Generally speaking, chemical extraction can be applied to most of the pretreatment and Purification. However, in thick-walled Gram-positive bacteria and some parasites, it is also the case that chemical extraction can not obtain effective nucleic acid templates, resulting in false negative detection. In addition, chemical extraction often uses strong agents, if the elution is not thorough, it is easy to introduce strong alkali into the reaction system, resulting in inaccurate results.

Ultrasonic fragmentation uses physical crushing, which has been successfully used by GeneXpert, a leading enterprise in the field of POCT for human use, and has an absolute advantage in nucleic acid extraction of some complex samples (such as Mycobacterium tuberculosis).

Therefore, it is recommended to select a test kit or instrument configured with a nucleic acid extraction step. and it is optimal if there is an ultrasonic extraction module.

3. Manual , Semi-automatic and fully automatic?
This is a problem of labor cost and work efficiency. At present, pet hospitals without enough staffs, and nucleic acid extraction and detection is a work that requires certain skills and experience. There is no doubt that the fully automatic nucleic acid extraction and detection machine is the perfect choice.

4. Constant temperature amplification or variable temperature amplification?
The amplification reaction is a nucleic acid detection link, and the professional technology involved in this link is complex. Roughly speaking, enzymes are used to amplify the nucleic acid. In the amplification process, the amplified fluorescence signal or the embedded fluorescence signal is detected. Generally speaking, the earlier the fluorescence signal appears, the greater the target gene content of the sample.

Constant temperature amplification is a nucleic acid amplification at a fixed temperature, while variable temperature amplification is a cyclic amplification strictly according to denaturation-annealing-extension. The constant temperature amplification time has been carried out, while variable temperature amplification time is greatly affected by the rate of temperature rise and fall of the instrument (at present, many manufacturers have been able to do 40 cycles of amplification in about 30 minutes).

If the laboratory conditions are good and the zoning is strict, it is reasonable to say that the accuracy difference between the two will not be great. However, variable temperature amplification will synthesize more nucleic acid products in a relatively shorter time. For laboratories without strict zoning and professional training personnel, the risk of nucleic acid aerosol leakage will be greater, the false positive occurs once leakage happens, and which is extremely difficult to eliminate.

In addition, Constant temperature amplification is also more prone to non-specific amplification when the sample is complex (the relative reaction temperature is lower, and the higher the extension temperature, the better the primer binding specificity).

As far as the current technology is concerned, variable temperature amplification is more reliable.

5. How to avoid the risk of leakage of nucleic acid amplification products?
At present, many manufacturers choose the gland type PCR tube as the nucleic acid reaction tube, which is sealed by friction, and the temperature denaturation in the variable temperature denaturation in the variable temperature PCR amplification reaches 90 degree
Centigrade . The repeated process of expansion with heat and contraction with cold is a great challenge to the sealing of the PCR tube, and the gland type PCR tube is relatively easy to cause leakage.

It’s preferable to adopt the reaction with a completely sealed kit/tube to avoid the leakage of the reaction product . It would be perfect if there could be work out a fully sealed kit for nucleic acid extraction and detection .

So New Tech’s new fully automatic nucleic acid extraction and detection machine has the above five optimal choices.