Understanding water structure on hydrophobic surfaces forward model-based process development for hydrophobic interaction chromatography
Hydrophobic interaction chromatography (HIC) is based on a separation of molecules with respect to their hydrophobicity.It is a commonly used method for intermediate steps and polishing steps in protein purification.
HIC process development generally relies on experimentation
HIC process development generally relies on experimental data. In contrast to ion exchange chromatography, HIC has intricate chromatographic behavior. The slow and volatile binding as well as the complex salt-dependent protein-ligand interaction is a challenge for modeling, especially for the derivation of suitable adsorption isotherm models.
New insights into water structure on hydrophobic surfaces
Various works in the area of hydrophobic surfaces were considered in order to derive a new mechanistic isotherm for modeling HIC. This model approach assumes an equilibrium between well-ordered and bulk-like ordered water molecules on the hydrophobic surface. Additionally, the hydration number of ions was considered as a function of the ionic strength to incorporate salt effects. This new isotherm was implemented in ChromX by means of its plug-in interface and is also available in the enterprise version of ChromX.
Prediction of protein adsorption and desorption behavior
With the new mechanistic isotherm, accurate HIC modeling could be realized. Using this concept, protein adsorption and desorption behavior for any given binding and elution salt concentration can now be predicted.