The Design of Advanced Functional Membranes for Bioseparations

Market demand is increasing rapidly for biotherapeutics such as recombinant proteins, monoclonal antibodies, viral vaccines and plasmid DNA. With the advent of molecular biotechnology and engineered cell lines, upstream production processes have made unprecedented progress in the last decade, shifting the production burden to the downstream processing. To improve process economics and meet market demand, manufacturers will require higher productivity and higher resolution separation techniques – membrane chromatography fulfills these requirements.

In this talk, I will describe our efforts to develop adsorptive membranes for use as chromatography media. I will describe the design and performance characterization of these materials and dispel two common misperceptions by showing that (1) membrane chromatography can be a higher capacity process than resin chromatography in the purification of biologics, and (2) membrane chromatography can be a higher resolution process than resin chromatography.

Our design approach is to graft polyelectrolyte nanolayers from the pore surfaces of macroporous membranes using a controlled polymerization method. Using a number of examples, I will demonstrate that the dynamic binding capacities of proteins and DNA can be dramatically higher for well-designed macroporous membrane adsorbers than for existing commercial membrane adsorbers and resin columns. Using controlled polymerization and high polymer chain density produces adsorptive membranes with high binding capacities that are independent of flow rate, enabling high-throughput operation.