Nucleic acid extraction reagents can be classified according to different principles and methods, mainly including the following categories:

Classification by Extraction Principle

• Nucleic Acid Extraction Reagents Based on Silica Membrane Adsorption
  These reagents utilize the property that silica membranes specifically adsorb nucleic acids under high – salt and low – pH conditions. When a sample containing nucleic acids comes into contact with the silica membrane, the nucleic acids are adsorbed onto the membrane, while impurities such as proteins and polysaccharides are eluted and removed. Finally, the nucleic acids are eluted from the silica membrane using an eluent with low – salt and high – pH conditions to obtain pure nucleic acids. Such reagents are relatively simple and rapid to operate, can effectively remove impurities, and are suitable for various sample types, such as blood, tissues, and cells. They are widely used in clinical diagnosis and scientific research fields.
• Nucleic Acid Extraction Reagents Based on Magnetic Beads
  The surfaces of magnetic beads are modified with groups that can specifically bind to nucleic acids. Under certain conditions, the magnetic beads bind to the nucleic acids in the sample, forming a nucleic acid – magnetic bead complex. By applying an external magnetic field, the complex can be separated from other impurities. After washing and elution steps, purified nucleic acids are obtained. These reagents have a high degree of automation, can achieve high – throughput extraction, and the nucleic acids are less likely to be sheared during the extraction process. They are suitable for large – scale sample testing and automated nucleic acid extraction platforms.
• Nucleic Acid Extraction Reagents Based on Phenol – Chloroform Extraction
  This method uses organic solvents such as phenol and chloroform to separate nucleic acids based on their different solubilities in proteins and nucleic acids. Phenol can denature and precipitate proteins, and chloroform can promote the separation of two phases, allowing the nucleic acids to remain in the upper aqueous phase. Through multiple extractions and centrifugations, impurities such as proteins can be removed. Then, organic solvents such as ethanol are used to precipitate the nucleic acids to obtain purified nucleic acid products. Nucleic acids extracted by this method have a relatively high purity, but the operation process is more cumbersome, and organic solvents such as phenol and chloroform are toxic to some extent, posing certain risks to operators and the environment.

Classification by Applicable Sample Types

• Blood Nucleic Acid Extraction Reagents
  These are specifically designed to extract nucleic acids from blood samples. For the cellular components in blood, such as red blood cells and white blood cells, as well as the free nucleic acids in plasma, specific lysis solutions and extraction methods are designed. They can effectively remove interfering substances in blood, such as hemoglobin and immunoglobulins, to obtain high – quality nucleic acids.
• Tissue Nucleic Acid Extraction Reagents
  Suitable for extracting nucleic acids from various tissue samples, such as animal tissues and plant tissues. Since the cell structures of tissues are relatively complex, these reagents usually contain strong lysis components that can break down the cell membranes, nuclear membranes, and other structures of tissue cells, release nucleic acids, and remove impurities such as proteins and polysaccharides in the tissues through subsequent purification steps.
• Microbial Nucleic Acid Extraction Reagents
  Used to extract nucleic acids from microorganisms such as bacteria, viruses, and fungi. According to the structural and compositional characteristics of the cell walls of microorganisms, corresponding enzymatic or chemical lysis methods are adopted to break the microbial cells, release nucleic acids, and then carry out targeted purification operations to obtain high – purity microbial nucleic acids.

Classification by Nucleic Acid Type

• DNA Extraction Reagents
  Mainly used to extract DNA from samples. Their formulations and operation procedures focus on protecting the integrity and purity of DNA, and removing impurities such as proteins and RNA that bind to DNA. In fields such as genomics research, genetic diagnosis, and forensic identification, DNA extraction reagents are important tools for obtaining genetic information.
• RNA Extraction Reagents
  Used to extract RNA from samples. Since RNA is easily degraded by RNases, these reagents usually contain components that inhibit the activity of RNases. During the extraction process, RNases can be rapidly inactivated to protect the integrity of RNA. RNA extraction reagents are of great significance in gene expression analysis, RNA virus detection, and mRNA vaccine research and development.

In addition, there are some special nucleic acid extraction reagents, such as mitochondrial DNA extraction reagents and viral nucleic acid extraction reagents. They are targeted at specific nucleic acid sources or application scenarios and have higher specificity and pertinence.