Anh Vu

Inverse colloidal crystal membranes for hydrophobic interaction membrane chromatography: Liquid Chromatography

Hydrophobic interaction membrane chromatography has gained interest due to its excellent performance in the purification of humanized monoclonal antibodies. The membrane material used in hydrophobic interaction membrane chromatography has typically been commercially available polyvinylidene fluoride. In this contribution, newly developed inverse colloidal crystal membranes that have uniform pores, high porosity and, therefore, high surface area for protein binding are used as hydrophobic interaction membrane chromatography membranes for humanized monoclonal antibody immunoglobulin G purification. The capacity of the inverse colloidal crystal membranes developed here is up to ten times greater than commercially available polyvinylidene fluoride membranes with a similar pore size. This work highlights the importance of developing uniform pore size high porosity membranes in order to maximize the capacity of hydrophobic interaction membrane chromatography.

Membrane-based hydrophobic interaction chromatography

ABSTRACT Hydrophobic interaction membrane adsorbers have been prepared using poly N-vinylcaprolactam as the binding ligand. The ligands were grafted using atom transfer radical polymerization. Binding and elution of lysozyme, bovine serum albumin, and IgG4 was investigated. At high ionic strength during loading, the ligand is above its lower critical solution temperature and adopts a dehydrated conformation. During elution in low ionic strength buffer, the ligand is below its lower critical solution temperature and adopts a hydrated conformation. Use of a responsive ligand could lead to improved performance. The importance of tailoring the three-dimensional structure of the ligands is shown.

Fouling of microfiltration membranes by biopolymers

ABSTRACT Suppression of fouling due to biopolymers of relevance to the brewing industry has been investigated. The effects of three model biopolymers: casein (protein), catechin (polyphenol), and dextran (polysaccharide) on fouling of asymmetric 0.65 μm polyethersulfone membranes during direct-flow filtration have been studied. While dextran is successful in disrupting interactions between casein and catechin, the associated reduction in aggregate size does not always result in reduced fouling. Solution conditions such as pH and ionic strength modulate the tendency of the aggregates to adsorb onto the membrane surface. Thus, optimizing solution conditions to suppress adsorption of aggregates is essential for increasing the membrane filtration capacity.