The effects of flux on the clearance of minute virus of mice during constant flux virus filtration.

Constant flux virus filtration experiments were conducted to evaluate minute virus of mice retention behavior of four commercial virus filters for continuous bioprocessing applications. Fluxes chosen were guided by the Peclet number and the processing logistics as well as based on the filter characteristics. At the low flux condition of 5 (LMH) when diffusive force dominates, a significant breakthrough was observed for all the filtrate fractions for the filtration of a low fouling monoclonal antibody for three of the four filters.

Optimization of Single-Column Batch and Multicolumn Continuous Protein A Chromatography and Performance Comparison Based on Mechanistic Model.

Expensive Protein A chromatography resins drive the need to maximize process productivity as well as resin capacity utilization. To this end, two strategies are explored. The first one is termed "super-batch," which utilizes a single short-bed-height column with rapid cycling to increase productivity, combined with variable load flow rates to enhance resin capacity utilization.

Advective hydrogel membrane chromatography for monoclonal antibody purification in bioprocessing.

Protein A chromatography is widely employed for the capture and purification of monoclonal antibodies (mAbs). Because of the high cost of protein A resins, there is a significant economic driving force to seek new downstream processing strategies. Membrane chromatography has emerged as a promising alternative to conventional resin based column chromatography.

Countercurrent tangential chromatography for large-scale protein purification.

Recent advances in cell culture technology have created significant pressure on the downstream purification process, leading to a "downstream bottleneck" in the production of recombinant therapeutic proteins for the treatment of cancer, genetic disorders, and cardiovascular disease. Countercurrent tangential chromatography overcomes many of the limitations of conventional column chromatography by having the resin (in the form of a slurry) flow through a series of static mixers and hollow fiber membrane modules. The buffers used in the binding, washing, and elution steps flow countercurrent to the resin, enabling high-resolution separations while reducing the amount of buffer needed for protein purification.

Characterizing the surface charge of synthetic nanomembranes by the streaming potential method.

The inference of the surface charge of polyethylene glycol (PEG)-coated and uncoated silicon membranes with nanoscale pore sizes from streaming potential measurements in the presence of finite electric double layer (EDL) effects is studied theoretically and experimentally. The developed theoretical model for inferring the pore wall surface charge density from streaming potential measurements is applicable to arbitrary pore cross-sectional shapes and accounts for the effect of finite salt concentration on the ionic mobilities and the thickness of the deposited layer of PEG. Theoretical interpretation of the streaming potential data collected from silicon membranes having nanoscale pore sizes, with/without pore wall surface modification with PEG, indicates that finite electric double layer (EDL) effects in the pore-confined electrolyte significantly affect the interpretation of the membrane charge and that surface modification with PEG leads to a reduction in the pore wall surface charge density.

Permeability - Selectivity Analysis for Ultrafiltration: Effect of Pore Geometry.

The effects of pore size on the performance of ultrafiltration membranes are fairly well understood, but there is currently no information on the impact of pore geometry on the trade-off between the selectivity and permeability for membranes with pore size below 100 nm. Experimental data are presented for both commercial ultrafiltration membranes and for novel silicon membranes having slit-shaped nanopores of uniform size fabricated by photolithography using a sacrificial oxide technique. Data are compared with theoretical calculations based on available hydrodynamic models for solute and solvent transport through membranes composed of a parallel array of either cylindrical or slit-shaped pores.

Purification of humanized monoclonal antibodies by membrane-based hybrid bioseparation technique.

We describe a rapid, inexpensive and scalable hybrid bioseparation technique for one-step purification of humanized monoclonal antibodies from mammalian cell culture supernatant. It involves the selective and reversible retention of the monoclonal antibody within a membrane module utilizing a combination of microfiltration of precipitated antibody and simultaneous hydrophobic interaction-based membrane chromatography of soluble antibody on the same microfiltration membrane. The retained monoclonal antibody is subsequently recovered from the membrane module in a highly pure form by changing the solution condition to that which favours simultaneous antibody dissolution and elution from the membrane.