Common types of chromatography resins

In downstream processing of biopharmaceuticals, chromatography technology is the key method in obtaining samples in high purity, with chromatography resins serving as core weapons for efficient purification and separation.  

The purification efficiency and product quality of pharmaceuticals are directly linked to the selection of resins.

Resins, as a major assistant in the purification of bio-molecules, are usually in extremely small sizes of several micrometers. Most resins are made of matrixes and functional groups, whose chemical and physical properties will usually determine the isolation performance of resins in the downstream purification.

Ideal chromatography resins should enjoy good performance in many aspects. However, reins made from different materials are inevitably having merits and demerits of their own. Thus, the choice of chromatography resin will eventually impact the process and results of purification.

In this article, Bestchrom will guide you through materials used for chromatography resin, as well as their advantages and limits.

Basic composition of chromatography resin

Resins are usually composed of matrix and functional groups. A good understanding of these factors is the first step to resin selection.

Table 1 concludes the properties of different resins as well as their applications.

Three types of common resin materials

Based on materials used for matrix, resins can fall into three categories:

Nature- sourced matrix resins

Chromatography resins made from modified carbohydrate polymers such as agarose and dextran, are referred as “soft resin”by some consumers.

Advantages:

• Good hydrophobicity, excellent bio-compatibility
• Wide application in big bio-molecules: For example, the  purification of antibody, recombinant protein and vaccines.

Disadvantages:

• Matrix is relatively softer than matrix made from polymer, which means it can only tolerate pressure lower than that of polymer.

Development:

• Resin manufacturers including Bestchrom have been producing resins based on highly rigid agarose for long time. The resins can tolerate pressure as high as 5 bar and meet the demand for most industrial scale-up productions.

Organic polymer matrix

For resins made from synthetic polymers such as cross-linked polystyrene, polymethacrylate, they enjoys high level of hydrophobicity as a result of special structure. For example: Polystyrene-divinylbenzene(PSDVB) enjoys good non-specific adsorption to bio-molecules including proteins. It is usually necessary to do modification on resin surface separating bio-molecules under most separation modes except for reversed phase chromatography.

Advantages:

• Tolerance to high pressure, big pore sizes for better pass-through. Suitable for the capture of target molecules from highly vicious and contaminated feedstock, as well as the polishing step in downstream purification.
• Larger surface area, providing higher binding capacity.

Disadvantages:

• High hydrophobicity of matrix, leading to non-specific adsorption
• Suitable for more modes after surface modification

Application

• For high load capture, polishing step or reverse phase chromatography

Inorganic matrix

Silica gel is a typical example in the category, which enjoys high rigid but poor acid tolerance. The material is usually used for normal/reversed phase chromatography resins. It is widely used for the separation of small molecules, especially in peptide and plant extraction. In addition, the resin can be packed in analytical chromatography columns.

Thanks to its advantages such as good mechanical strength, solvent tolerance, controllable surface area and pore size, non-swelling, incompressibility, as well as the surface silicon hydroxyl for easy bonding and modification, Silica gel becomes one of the earliest HPLC resins with most extensive applications. Besides, the resins are  mainly for lab-scale analytical chromatography and small molecule separation at industrial scale.

However, the instability under acid/alkali condition of silica gel makes it unsuitable for the purification under alkali condition, leading to its rare application in the separation of big bio-molecules.

Advantages:

• High rigidity, uniform pore size, high resolution
• Good tolerance to organic solvents, suitable for HPLC

Limitations

• Poor alkali stability, limited life time
• Not suitable for the separation of big bio-molecules.

Application

• Widely applicable in the purification of small bio-molecules, peptide, extraction of plants and HPLC analysis.

Tips for resin selection and future prospect

• Big bio-molecules(antibody, vaccine, plasmid , etc)—agarose-based resins are first-options
• High strength, high throughput scenario--- Polymer-based resins enjoy more advantages
• Analysis and small molecule separation---silica-based resins are first-option

Conclusion

The material of chromatography resin, function as the base of purification process, directly impacts the application prospects and stability of the process.

Agarose matrix: good bio-compatibility, playing a leading role in the purification of bio macro-molecules.

Polymer matrix: good mechanical strength, good chemical stability, suitable for the process of high throughput and high load.

Silica matrix: uniform pore size, high resolution, being an ideal option for small molecules purification and chromatography analysis.

A comprehensive understanding of features of different materials enables the right choice of resins tailored for purification process, contributing to a more efficient and stable separation.

Reference

[1] Starry Pure World: Knowledge Sharing: How Much Do You Know About Choosing Chromatography resin matrixes?

https://mp.weixin.qq.com/s/yiompY92uqQMFgnx3M9_wA

[2] Bestchrom: Understand the Four Core Chromatography Principles in One Article and Lay a Solid Foundation for Purification.

https://mp.weixin.qq.com/s/5mrO0P_BebR-wct1PC2EoQ

[3] zhihu: bio-pharmaceutical upstream project (5) : chromatographic packing, https://zhuanlan.zhihu.com/p/521668085

[4] Research on New Protein Chromatographic Media. Zhou Xin, School of Chemical Engineering, Tianjin University

[5] Preparation and Application of New and Highly Efficient Separation Media. Zhang Lei, School of Pharmaceutical Science and Technology, Tianjin University

[6] Introduction to “Comparison between the efficiencies of columns packed with fully and partially porous C18-bonded silica materials” by F. Gritti, A. Cavazzini, N. Marchetti, G. Guiochon[J. Chromatogr. A 1157 (2007) 289–303]