Nucleic acid extraction is a routine procedure used in molecular biology as a beginning for numerous downstream applications, including fundamental research and routine diagnostics tests. In fact, almost every process in molecular biology requires high quality DNA or RNA. Therefore, the importance of achieving the finest extraction performance cannot be underestimated, particularly when satisfying complex downstream applications.

During DNA extraction, DNA is freed from the cells and is separated from other cellular components to acquire pure DNA extracts. Extracted DNA is useful for scientific and forensic purposes. In this blog, we will discuss about the most commonly employed technology for DNA extraction, the Spin Column method.

 

Understanding DNA extraction:

DNA extraction serves as the foundational step for numerous molecular biology techniques and experiments, forming an essential cornerstone in the realm of biological research. In order to study the DNA, you first have to separate it from the cell. This is precisely what DNA extraction is.

 

DNA extraction is often used interchangeably with DNA isolation and DNA purification. However, there is a slight difference: DNA isolation collects as much pure DNA as possible. DNA purification eliminates the contamination present in DNA, while DNA extraction is a way to achieve both isolation and purification.

 

Where do we get DNA?

The source of DNA extraction can be very diverse. Basically, DNA can be extracted from living as well as dead organisms. Common sources include human specimens like blood, saliva, hair, bone, semen, etc. Furthermore, DNA can also be obtained from any kind of plants or animal tissues. Even stored sample or archived samples can be used to extract DNA.

 

DNA is found within the cells, either in the nucleus or the cytoplasm. One of the most important factors to consider while understanding the DNA extraction procedure is understanding that along with DNA, there are components such as enzymes, proteins and several organic/inorganic components. These components need to be removed from the sample during the extraction procedure.

 

DNA Spin Column Basics:

DNA spin Column is a commonly used technique to purify DNA from cells and tissues. It is also called the solid-phase extraction technique. In simple terms, this technique uses a solid matrix, such as silica, packed in a column that selectively binds to specific molecules and lets other molecules pass through from the starting material (blood/tissues). With this technique, we are able to get DNA to bind. Next, we wash everything off and then let DNA to unbind by manipulating the conditions inside the spin column. Let us understand in detail how the Spin Column works exactly.

 

 

How does Spin Column work:

The DNA purification process involves several steps that utilize the unique properties of DNA molecules and the design of the spin column. As mentioned above, DNA isolation or extraction is the basis of several molecular biology procedures.

 

Here's how the DNA spin column purifies DNA:

• Lysis: The nuclear membrane, cell membrane, and cell walls are lysed to release the DNA. This process is also referred to as cell disruption because it involves in splitting open the cell. In the beginning of the lysis procedure, it is essential to first culture the cells. After cell culture, during lysis step, a chemical buffer or mechanical method disrupts the lipid membrane and enables target molecules to leave the cell.
  Mechanical lysis: It is crucial in plant cells since they have rigid cell walls. This can be done by using a blender, mortar, or a homogenizer.
  
  Chemical lysis: Chemical lysis is performed using chemical mixtures like detergents and enzymes to cause the rapid disruption of the membrane to release its contents. Enzymes are also used to directly target amino acids to remove protein since only nucleic acid is needed from the sample. Depending on the sample types, common enzymes used in the buffer are Proteinase K, Cellulase, and Lyticase.

• Binding: After the completion of lysis, the released nucleic acid is transferred to the DNA spin column. This step aims to bind the DNA to the silica matrix in the column. This step involves the use of buffers containing chaotropic salt and ethanol.
  DNA and silica are both negatively charged so they repel each other and bind to water via a hydrogen bond. Salts create an ideal environment for DNA by weakening their bonds with water and effectively binding DNA to the silica membrane. The binding buffer effectively maintains the pH level in the process and ensures that DNA effectively binds with the silica. The alcohol further stabilizes DNA by dehydration.

• Washing: Even though DNA successfully separates from the nucleus during lysis process, certain binding salts and lysis chemicals can be present with the isolated DNA. Hence in this stage, a wash buffer is used in the spin column to force out the impurities from the membrane, leaving just the DNA bound to the silica gel. The wash is usually done twice: first with a low chaotropic salt concentration and second with ethanol.

• Elution: The final step of DNA extraction is elution. The purified DNA is bound to the silica membrane after the wash. The wash buffer is replaced with an elution buffer (either low salt buffer or just water). This rehydrates the DNA and separates it from the silica membrane which is then collected in the base of the SPIN column. This purified form of DNA can then be effectively used for several downstream applications.

• Centrifugation: The entire spin column DNA extraction process is facilitated by centrifugation. During each step, the column is placed in the centrifuge tube, and centrifugation forces are used to isolate the DNA efficiently.
  This blog is intended to help you understand the science behind spin column purification of DNA so that you can get the best out of your DNA extraction. However, selecting the suitable spin column kit will vary according to your sample and application type. At MP Biomedicals, we provide a wide range of nucleic acid extraction kits for your convenient use.
  
  Explore the wide range of SPIN Column-based Extraction Kits by MP Biomedicals from https://heyzine.com/flip-book/39f07e842d.html
  
  Need additional assistance? Our Technical team is available to guide you in selecting the right product according to your sample types.