Host cell protein (HCP) contaminants accumulate during bioprocess recovery of desirable proteins (eg. mAbs) and result in the need for and disposal of large amounts of buffer. Electrostatic adsorptive capture of these contaminants using charged membranes is often used near the end of the recovery process. In this presentation, we will demonstrate how a new class of high surface area charged branched brush membrane adsorbers outperformed commercial competitors currently used in industry. These novel polymer brush membranes were synthesized using a modified Atom Transfer Radical Polymerization (ATRP) method together with hydrophilic regenerated cellulose membranes with pore sizes of about 3 µm or greater. The resulting membranes were challenged with BSA as a model HCP similar to that used by Pall Corp. and Sartorius Stedim Biotech. Dynamic binding capacity were determined from a 10% dynamic breakthrough curve. The filtration of BSA protein solutions using brush membranes were conducted in low ionic strength buffer in a 25 mm Pall in-line filter holder. The adsorbed proteins are then eluted with high ionic strength after the system is washed with the binding buffer. These high surface area charged branched brush membrane adsorbers not only reduce buffer waste and processing times but can also be used to recover recombinant protein aggregates for increased yield. The membranes were characterized using ATR-FTIR spectroscopy, X-Ray Photoelectron Spectroscopy and Scanning Electron Microscopy.

Contaminant removal from a purified protein stream

2019 Spring National Meeting

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