How to Purify Oligonucleotides?
As a trusted oligonucleotide supplier, I understand the crucial role that high – quality oligonucleotides play in a wide range of biological and biochemical research, as well as in diagnostic and therapeutic applications. Oligonucleotide purification is a vital step in the production process, ensuring that the final product meets the high – standards required for these demanding applications. In this blog, I’ll share with you the different methods of oligonucleotide purification, their advantages, disadvantages, and how we implement them to provide you with the best oligonucleotide products. Oligonucleotide
Why Purify Oligonucleotides?
Before delving into the purification methods, it’s essential to understand why purification is necessary. During the chemical synthesis of oligonucleotides, several by – products can be generated. These include truncated oligomers (failed sequences that are shorter than the desired length), protecting groups that were not entirely removed, and salts from the synthesis buffers. These impurities can interfere with the accuracy and reproducibility of downstream applications. For example, in PCR experiments, truncated oligomers may act as non – specific primers, leading to false – positive results. In therapeutic applications, impurities can cause unwanted immune responses or side effects. Therefore, purification is crucial to obtain pure, full – length oligonucleotides with high biological activity.
Popular Oligonucleotide Purification Methods
1. Cartridge Purification
Cartridge purification is one of the most commonly used methods for oligonucleotide purification, especially for small – scale production. This method is based on the principle of differential binding of full – length oligonucleotides and impurities to a solid – phase matrix in the cartridge.
The matrix in the cartridge is often a reversed – phase resin. When the crude oligonucleotide mixture is passed through the cartridge, full – length oligonucleotides bind more strongly to the resin due to their longer nucleotide chains and higher hydrophobicity compared to truncated oligomers and other impurities. After washing away the impurities with a low – strength elution buffer, the full – length oligonucleotides are eluted with a high – strength buffer.
The advantages of cartridge purification are its simplicity and relatively low cost. It can be easily performed in a laboratory setting without the need for expensive equipment. However, the purity achieved by cartridge purification is usually moderate, and it may not be sufficient for applications that require extremely high – purity oligonucleotides.
2. Polyacrylamide Gel Electrophoresis (PAGE)
PAGE is a powerful purification method that separates oligonucleotides based on their size and charge. In this method, the crude oligonucleotide mixture is loaded onto a polyacrylamide gel, and an electric field is applied. Oligonucleotides migrate through the gel at different rates depending on their size, with smaller oligonucleotides moving faster than larger ones.
After electrophoresis, the gel is stained to visualize the oligonucleotide bands. The band corresponding to the full – length oligonucleotide is excised from the gel. The oligonucleotides are then recovered from the gel slice by methods such as electroelution or diffusion.
PAGE can achieve very high purity, as it can effectively separate oligonucleotides with a single – base difference in length. However, it is a time – consuming and labor – intensive method. The process of excising the gel slice and recovering the oligonucleotides requires careful handling to avoid contamination and loss of product.
3. High – Performance Liquid Chromatography (HPLC)
HPLC is a widely used purification method in the field of oligonucleotide production. It can be further divided into different types, such as ion – exchange HPLC and reversed – phase HPLC.
Ion – exchange HPLC: This method separates oligonucleotides based on their charge. The stationary phase in ion – exchange HPLC is a resin with charged functional groups. Oligonucleotides bind to the resin through electrostatic interactions, and the strength of the binding depends on the number of phosphate groups in the oligonucleotide chain. By gradually changing the ionic strength of the mobile phase, different oligonucleotides can be eluted from the column at different times.
Reversed – phase HPLC: As mentioned earlier, it separates oligonucleotides based on their hydrophobicity. The stationary phase is a hydrophobic material, and the mobile phase is a mixture of water and an organic solvent. Full – length oligonucleotides, with their relatively higher hydrophobicity, are retained longer on the column compared to impurities.
HPLC offers high resolution and can be easily automated, making it suitable for large – scale production. However, it requires expensive equipment and skilled operators.
4. Capillary Electrophoresis (CE)
CE is a separation technique that uses an electric field to separate analytes in a capillary tube filled with a buffer solution. It separates oligonucleotides based on their electrophoresis mobility, which is related to their charge – to – size ratio.
CE provides high – resolution separation similar to PAGE but with several advantages. It is faster than PAGE, requires less sample, and can be easily automated. However, the equipment for CE can be expensive, and the choice of buffer and separation conditions needs to be carefully optimized.
Our Approach as an Oligonucleotide Supplier
At our company, we take a comprehensive approach to oligonucleotide purification. We start by carefully selecting the appropriate purification method based on the specific requirements of the oligonucleotide product. For small – scale orders where moderate purity is sufficient, we may use cartridge purification. When high – purity oligonucleotides are needed, such as for therapeutic or high – precision research applications, we turn to methods like HPLC or PAGE.
We also implement strict quality control measures throughout the purification process. After purification, we use analytical techniques such as mass spectrometry and capillary electrophoresis to verify the purity and identity of the oligonucleotides. This ensures that the final product meets the high – standards expected by our customers.
In addition, we continuously invest in research and development to improve our purification methods. We are exploring new materials and techniques to increase the efficiency and purity of oligonucleotide purification while reducing the cost and environmental impact.
Conclusion
Purifying oligonucleotides is a complex but essential process to obtain high – quality products for various applications. There are several purification methods available, each with its own advantages and disadvantages. As an oligonucleotide supplier, we are committed to using the most appropriate and advanced purification techniques to ensure the purity and quality of our products.
API If you are in need of high – quality oligonucleotides for your research, diagnostics, or therapeutic projects, we would love to discuss your requirements with you. Our team of experts can provide you with the best solutions and support to meet your specific needs. Contact us to start a conversation about your oligonucleotide procurement.
References
- Kumar, P., & Poon, R. (2014). Oligonucleotide purification techniques: Progress and prospects. Journal of Chromatography B, 965, 118 – 128.
- Sheu, W. S., & Juo, R. R. (2011). Purification of DNA oligonucleotides by high – performance liquid chromatography: A review. Journal of Chromatography A, 1218(45), 7991 – 8003.
- Urdaneta, R., & De la Escosura – Muñiz, A. (2019). Oligonucleotide purification: From classical to advanced separation techniques. Analytica Chimica Acta, 1095, 1 – 18.
Zhejiang Hengkang Pharmaceutical Co., Ltd.
Zhejiang Hengkang Pharmaceutical Co., Ltd. is well-known as one of the leading oligonucleotide manufacturers and suppliers in China. With a professional production team, we are able to meet the needs of the majority of our customers. Please feel free to wholesale bulk high quality oligonucleotide from our factory.
Address: No.11 Chengen Road, Pubagang Town, Sanmen County, Zhejiang Province, China.
E-mail: commercial@hengkangpharm.cn
WebSite: https://www.hengkang-pharm.com/
