Diffusion Split-Flow Thin Cell (SPLITT) system for protein separations

A diffusion Split-Flow Thin Cell (SPLITT) system was used to partially remove small peptides such as β2 microglobulin (β2M) and parathyroid hormone (PTH) in a continuous manner from an input flow stream while preserving most (over 97%) of the larger protein in the sample, such as albumin. To help determine the operating conditions for this work, a two-dimensional numerical model based on the Navier–Stokes equation and convection–diffusion equations was developed for diffusional SPLITT using COMSOL multiphysics software (COMSOL Inc., MA). These simulations were used to obtain the relationship between important operational parameters and the purification efficiency for proteins of interest. The diffusion-based SPLITT system was fabricated using xurography and was used to demonstrate protein purification based on the differences in size or diffusion coefficient of the sample. The results obtained from the experiments are compared with the mathematical model and show good agreement, while the variations between these results are discussed. The results show that significant portions of small peptides (>25%) can be removed while preserving larger proteins (up to 95%) in the carrier stream. A potential application of this technique is to be used as an additional step in kidney dialysis to remove toxins that are not effectively removed by current dialysis protocols.