Selective displacement chromatography in multimodal cation exchange systems.

Area of Science:

• Biochemistry
• Chromatography
• Chemical Engineering

Background:

• Multimodal (MM) chromatography offers enhanced selectivity for protein separation.
• Optimizing displacer molecules is crucial for maximizing MM chromatography performance, especially under high loading conditions.

Purpose of the Study:

• To evaluate a library of displacer analogues for their ability to enhance protein separation selectivity in MM chromatography.
• To identify key displacer properties that improve protein displacement and separation efficiency.

Main Methods:

• Screening a library of displacer analogues with varying electrostatic, hydrophobic, and hydrogen bonding properties.
• Utilizing robotic liquid handling for high-throughput screening and batch separations.
• Performing column chromatography studies to assess separation performance under selective displacement and desorption modes.

Main Results:

• Selective batch separations were achieved for previously inseparable proteins.
• Displacers with higher hydrophobicity and net charge demonstrated improved protein displacement.
• Proteins binding primarily via electrostatic interactions were more readily displaced than those with significant hydrophobic contributions.
• Multimodal displacers showed higher selectivity than single-mode electrostatic displacers.
• Baseline separations were achieved for model protein pairs using selective displacement and desorption modes.

Conclusions:

• The inherent selectivity of MM resins can be augmented by displacer selectivity under non-linear competitive binding conditions.
• This approach creates new opportunities for protein separations beyond traditional gradient operations.
• Optimized displacer design is key to unlocking the full potential of MM chromatography for complex protein mixtures.