Over the past few decades, there has been a great interest in exploring alternatives to conventional packed-bed chromatography for protein purification. Although membrane filtration offers a potentially attractive alternative, membrane fouling has been an impediment to practical use. To address this problem, we are exploring the potential of using organic-inorganic hybrid membranes.

In this study, AnoporeTM alumina membranes with macropores of 200nm diameter (Whatman) were explored as membranes that could subsequently be functionalized. The fouling behavior before functionalization, and after a variety of surface modifications will be reported for bovine serum albumin (BSA) (pI 4.7) and lysozyme (pI 11.0) using a stirred cell filtration system to determine the fouling and the flux decline during filtration. In short, the results show that the fouling behavior can be modified through a judicious choice of surface functionalization. The F108 (EO132PO56EO132, BASF) functionalized surfaces showed a substantive reduction in fouling, even at low polymer content (~1-2 wt%). TGA and IR spectroscopy were performed in conjunction with the fouling studies to understand the results in terms of the surface chemistry. Current work, which will also be reported, is 1) studying membranes with higher functional group loading, 2) surface tethered macromolecules (PEG, poly-L-lysine) and their effect on fouling, and 3) preliminary modeling of the flux data.