Introduction to High-Capacity Ion Exchange Chromatogra Media

Ion exchange chromatography, as the most classic separation mode in the field of biomacromolecule separation and purification, currently occupies a considerable market share. The basic mechanism for separating proteins using ion exchange chromatography is that proteins can be separated through the interaction between their charges and the net charge on the surface of the media.

In recent years, the biopharmaceutical industry has developed rapidly, with a high demand for drug production. This necessitates purification media with high dynamic binding capacities to produce high-purity drugs that meet market demands. Therefore, the ultimate goal of ion exchange chromatography research is to develop ion exchange chromatography media with high dynamic binding capacities and selectivity. Globally, major manufacturers of ion exchange chromatography media are primarily focused on developing new high-capacity ion exchange chromatography media.

Factors Affecting the Dynamic Binding Capacity of Ion Exchange Chromatography

There are many factors that influence the dynamic binding capacity of ion exchange chromatography. In addition to the pH of the mobile phase, ionic strength, and flow rate, these factors include the ligand density of the media, the length of the spacer arms between the ligands and the base matrix, and the connection method. For the separation and purification of biomacromolecules, the accessibility of the surface charges of these large molecules is low due to their large volume. Therefore, longer spacer arms are more beneficial as they enhance the interaction between the ionic functional groups on the media surface and the charged functional groups of the biomacromolecules.

In traditional chromatography media, linear spacer arms are used. These linear spacer arms can become entangled with biomacromolecules during separation, leading to low column efficiency. Dendritic macromolecules, with their perfect three-dimensional tree-like structures, effectively solve the limitations of the microsphere's finite surface area for grafting functional groups and the steric hindrance encountered during the grafting process. This achieves the goal of high dynamic binding capacity.

Matrix of Ion Exchange Chromatography Media

The matrix of ion exchange chromatography media primarily includes polysaccharide materials such as agarose and dextran, as well as polymers like polystyrene and polyacrylate. The advantages of polysaccharide matrices are their extremely high hydrophilicity, low non-specific adsorption of proteins, and the presence of numerous hydroxyl groups on the surface that can be activated.

Currently, Welch Materials' ion exchange chromatography media primarily utilize agarose as their main component. This includes the Q/SP Tanrose XL high-capacity agarose-based ion exchange media, with the basic parameters listed in the table below. The BSA protein adsorption capacity of Q Tanrose XL strong anion exchange resin can reach 130 mg/mL, while the lysozyme adsorption capacity of SP Tanrose XL strong cation exchange resin is even higher, reaching up to 160 mg/mL.

This product employs a 6% agarose matrix with dextran as its extending arms. The resulting dextran grafting layer provides a three-dimensional adsorption space, facilitating protein adsorption. Simultaneously, grafting dextran improves the charged environment on the agarose microspheres' surface, reducing non-specific adsorption. The presence of the dextran layer promotes mass transfer through effects such as electrostatic coupling.

Ion functional groups are bound to the dextran, increasing the density of functional groups while reducing spatial hindrance between the bound biomolecules. This significantly enhances binding capacity, ensuring the ability to process samples under high flow rate conditions. It is suitable for initial capture and moderate purification of various scale biomolecules.

Summary and Outlook

In addition to polysaccharide-based ion exchange chromatography fillers, polymer microspheres have advantages such as high mechanical strength and good chemical stability. Moreover, the size and particle size distribution of such microspheres are easier to control, facilitating column packing and exhibiting good porosity, resulting in high separation efficiency. Therefore, they are also ideal carriers for chromatography media.

Welch has been deeply involved in the field of high-capacity ion exchange chromatography media for many years. In addition to the existing agarose-based matrix, Welch will continue to enrich polymer-based high-capacity protein purification fillers.