1. Divide according to the size of the instrument model [1]?
1) Automatic liquid workstation
The automatic liquid workstation is a very powerful device. Liquid, aspiration, etc. are automatically completed. It can even realize full automation of specimen extraction, amplification, and detection by integrating functions such as amplification and detection. Extracting nucleic acids is only one application of its function and is not suitable for routine laboratory extraction of nucleic acids. It is generally used in experimental requirements where a single type of specimen is extracted and a very large amount of specimens are extracted at one time (at least 96, usually several hundred). The establishment and operation of the automatic workstation platform require relatively large funds.
2) Small automatic nucleic acid extraction instrument
Small automatic instruments achieve the purpose of automatically extracting nucleic acids through the particularity of the operating structure and can be applied in any laboratory.
2. Divide according to different extraction principles
1) Instruments using the spin column method
The spin column method nucleic acid extraction instruments mainly use centrifuges and automatic pipetting For the method of combining devices, the throughput is generally 1-12 samples, and the operation time is about the same as manual extraction. It cannot improve the actual work efficiency, and it is expensive. The consumables of different types of instruments cannot be used universally. It is only suitable for large-scale experiments with sufficient funds. room use.
2) Instruments that use the magnetic bead method
Use magnetic beads as carriers, use magnetic beads to adsorb nucleic acids under high salt and low pH values, and combine with nucleic acids under low salt and high pH values The principle of separation is to realize the entire extraction and purification process of nucleic acids by moving magnetic beads or transferring liquid. Due to the uniqueness of its principle, it can be designed into many kinds of flux, which can extract either a single tube or 8-96 samples. The operation is simple and fast. It only takes 30-45 minutes to extract 96 samples, which greatly improves the efficiency. Experimental efficiency and low cost, so it can be used in different laboratories, is the mainstream instrument on the market.
Basic principles of magnetic bead nucleic acid extraction instruments
Magnetic bead nucleic acid extraction instruments are generally divided into two types: suction method and magnetic rod method[2]?:
1. The aspiration method, also called the pipetting method, is to extract nucleic acids by fixing magnetic beads and transferring liquid. The transfer is generally achieved by controlling a robotic arm through an operating system. The extraction process is as follows:
1) Lysis: Add lysis solution to the sample, mix the reaction solution and fully react through mechanical movement and heating, lyse the cells, and release nucleic acids.
2) Adsorption: Add magnetic beads to the sample lysis solution, mix thoroughly, and use the magnetic beads to have strong affinity for nucleic acids under high salt and low pH values ??to adsorb nucleic acids and apply an external magnetic field. , separate the magnetic beads from the solution, use the suction tip to remove the liquid and discard it to the waste tank, and discard the suction tip.
3) Washing: Remove the external magnetic field, use a new tip, add washing buffer, mix thoroughly, remove impurities, and remove the liquid under the action of the external magnetic field.
4) Elution: Remove the external magnetic field, use a new tip, add the elution buffer, mix thoroughly, and the bound nucleic acid will be separated from the magnetic beads, thereby obtaining the purified nucleic acid.