Comparison of the Advantages and Disadvantages of Several DNA Extraction Methods

In nature, whether it is plants, animals or viruses, as the genetic material of most organisms, DNA plays an irreplaceable role in genetics. In order to study biological genes, DNA needs to be extracted from cells, which can be achieved through many methods. Currently, the commonly used methods include phenol chloroform extraction method, spin column method, and magnetic bead method. We has sorted and compared these three extraction methods, and summarized the advantages and disadvantages of each method for reference by researchers.

1 Phenol Chloroform Extraction Method

Phenol chloroform extraction of DNA utilizes phenol as a protein denaturant, which is repeatedly extracted to denature the protein. SDS (sodium dodecyl sulfonate) cleaves the cell membrane, digests the protein or peptide or small peptide molecules in the presence of protease K and EDTA, denatures and degrades the nuclear protein, allowing DNA to dissociate from the nuclear protein. DNA is easily soluble in water, but not in organic solvents.

The surface of protein molecules carries hydrophilic groups, which are also prone to hydration and form a hydration layer on the surface, allowing protein molecules to smoothly enter the aqueous solution and form a stable colloidal solution. When organic solutions exist, the colloidal stability of proteins is disrupted and denatured and precipitated. After centrifugation, the organic solvent is present in the bottom layer (organic phase) of the test tube, DNA is present in the upper aqueous phase, and proteins are precipitated between the two phases. Using the principle of extraction, protein nucleic acids are dissolved in different reagent layers, and the tip is inserted into different liquid layers to extract the required components. After multiple washings, purified nucleic acids are obtained.

The disadvantage of this method is that it uses reagents such as phenol and chloroform, which have high toxicity. Long term operation has a significant impact on the health of the personnel, and the recovery rate of nucleic acid is low, resulting in significant losses. Due to the large operating system, the repeatability of different experimental personnel is poor, which is not conducive to protecting RNA and making it difficult to perform micro?operation. The advantage is that it uses common laboratory reagents and drugs, which is relatively low-cost to produce.

2 Spin Column Method

The main principle of spin column column method is to fix functional groups that have adsorption on nucleic acid on the spin column mold, and add different lysis reagents, washing reagents, and repeated centrifugation to obtain purified nucleic acid. The advantage of spin column method for DNA extraction is that it has higher purity than traditional phenol chloroform method, which is beneficial for RNA protection, and can perform micro operations. With its low price and relatively convenient operation, it gradually replaces traditional DNA extraction methods and is widely accepted in markets such as universities and research institutes.

The disadvantage of spin column method for DNA extraction is that it requires a large number of samples and consumables, making it powerless for rare samples, especially in fields such as forensic medicine and archaeology. At the same time, the spin column method for DNA extraction requires repeated centrifugation, which is not convenient for high-throughput and automated operations, and is incompatible with the high-throughput and automated requirements of modern biological experiments. Especially in fields such as gene diagnosis, disease detection, and transgenic testing, the spin column method for DNA extraction requires a large number of operators and equipment. When facing sudden outbreaks, it is even more necessary to have high-throughput DNA extraction equipment and methods to more effectively and accurately monitor and control the epidemic. A new DNA extraction method is needed to address this practical challenge. Driven by the trend of this era, magnetic bead method for DNA extraction has emerged.

3 Magnetic Bead Method

The principle of magnetic bead method is to modify the surface of magnetic beads with specific active functional groups that can adsorb nucleic acids. Through different lysis solutions and washing solutions, they can specifically bind to the target substance under specific conditions. At the same time, by utilizing the magnetic properties of the magnetic beads themselves, they can easily achieve directional movement and enrichment under the action of an external magnetic field, so as to achieve the purpose of separating nucleic acids and impurities, and then realize the separation and purification of the target substances and obtain purified nucleic acids.

The magnetic bead method is a perfect combination of nanotechnology and biotechnology, with advantages that other DNA extraction methods cannot compare, mainly reflected in:

a.?Being able to achieve automation and high-throughput operations, combined with a 96-well nucleic acid automatic extractor, it can simultaneously process 96 samples within the extraction time of a single sample in the past, directly improving the efficiency by 96 times, meeting the requirements of current biological high-throughput operations and enabling rapid screening of causes during large-scale outbreaks. This advantage is difficult for other methods to catch up with.

b.?Simple operation and short time. The entire extraction process can only be completed in four short steps: lysis, binding, washing, and elution.

c.?Safe and non-toxic, it does not use toxic reagents such as benzene and chloroform in traditional methods, causing minimal harm to experimental operators and protecting their physical health.

d.?The specific binding between magnetic beads and nucleic acids results in high purity and concentration of extracted nucleic acids.

?e.?High sensitivity, suitable for micro DNA extraction from forensic samples.

With the rapid development of contemporary biology and the widespread use of nucleic acid extraction instruments, in order to meet the requirements of the times, ALLSHENG has developed magnetic bead DNA extraction and multiple series solutions for magnetic bead DNA extraction, providing strong technical support and product support for scientific researchers to improve experimental efficiency and simplify the experimental process. Magnetic bead DNA extraction will also become the mainstream of modern molecular biology.