Working Principle of Automatic Nucleic Acid Extractor

There are several main working principles of automatic nucleic acid extractor:
Magnetic bead method
Sample lysis: firstly mix the sample (such as blood, saliva, tissue, etc.) with lysate, the components in the lysate will destroy the cell structure, make the cell lysed and release nucleic acid.
Nucleic Acid Binding: Magnetic beads are added to the lysate, the surface of the beads has specific functional groups which can specifically bind to the nucleic acid molecules, forming a nucleic acid – magnetic bead complex.
Wash purification: The magnetic beads adsorbed with nucleic acids are separated from the impurities in the solution by the magnetic field, and then the beads are washed several times with washing buffer to remove the residual proteins, cellular debris, and other impurities to further purify the nucleic acids.
Nucleic acid elution: Change the conditions of the solution, such as pH value, salt concentration, etc., so that nucleic acid is eluted from the magnetic beads and collected into a clean container to obtain the purified nucleic acid.
Centrifugal column method
Sample treatment and lysis: As with the magnetic bead method, the sample is first pre-treated so that its cells are lysed and nucleic acids are released.
Nucleic acid binding: The lysed sample is added to the centrifugal column, where adsorbent materials such as silica membranes selectively adsorb the nucleic acid molecules under specific conditions, while impurities are removed by centrifugation.
Wash: The nucleic acids adsorbed on the centrifuge column are washed by centrifugation with washing solution to remove impurities and improve the purity of nucleic acids.
Elution: Finally, an elution solution is added to desorb the nucleic acids from the adsorbent material and collect them in a centrifuge tube to complete the extraction of nucleic acids.
Liquid-liquid extraction method
Sample preparation and lysis: the sample is first lysed to release the nucleic acids, and then organic and aqueous phase solutions are added to distribute the nucleic acids into the aqueous phase.
Extraction: The aqueous phase and organic phase are stratified by centrifugation or other means, and the aqueous phase containing nucleic acids is transferred to a new container, at which time the nucleic acids are initially separated from some of the impurities.
Precipitation: add precipitating agent to make nucleic acid precipitate out under specific conditions, and then collect the precipitate by centrifugation to get the crude extract of nucleic acid.
Dissolution and purification: dissolve the precipitated nucleic acid in appropriate buffer, and further remove the residual impurities by filtration, dialysis, etc., to obtain high-purity nucleic acid .