Modeling protein binding and elution over a chromatographic surface probed by surface plasmon resonance

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Surface Plasmon Resonance (SPR) spectroscopy is a powerful label-free optical technique.
• Ion-exchange chromatography is widely used for protein purification.
• Characterizing protein-surface interactions is crucial for biomaterial and bioprocess development.

Purpose of the Study:

• To develop and validate a scaled-down analytical tool for protein binding and elution analysis.
• To create a mathematical model for interpreting SPR sensorgrams under cyclic sorption conditions.
• To quantitatively describe the adsorption and elution kinetics of bovine serum albumin (BSA) on a diethylaminoethyl (DEAE) functionalized surface.

Main Methods:

• Immobilization of diethylaminoethyl (DEAE) ligand onto a gold sensor chip via a self-assembled monolayer of 11-mercaptoundecanoic acid.
• Utilizing Surface Plasmon Resonance (SPR) spectroscopy to monitor protein binding and elution.
• Developing and applying a mathematical adsorption rate model to analyze SPR sensorgrams.

Main Results:

• A micrometric-scale adsorption surface with immobilized DEAE ligand was successfully created.
• An explicit mathematical formulation was provided for SPR sensorgram deconvolution.
• The proposed adsorption rate model quantitatively described BSA binding and elution across a range of protein concentrations and salt conditions.

Conclusions:

• SPR spectroscopy can serve as a valuable pseudo-chromatography tool for analyzing protein-surface interactions.
• The developed adsorption rate model accurately predicts protein binding and elution behavior.
• This approach offers a quantitative method for characterizing protein adsorption dynamics on ion-exchange surfaces.