(147b) Nature Inspired Convective Chromatography Columns for Preparative Separations

Continuous biomanufacturing is underlining the limits of the conventional chromatographic process based on packed bed columns, whose diffusion as primary transport phenomena and unsolvable bed inhomogeneity are the primary causes of performance reduction. From this perspective, open tubes and regular array columns showed a great potential, with significantly higher efficiency when compared to conventional columns. However, their application is currently confined to analytical separations of nano- and micro-samples, due to several limitations mainly related to the low surface area available for adsorption (owing to the absence of small diffusive pores) and to the manufacturing techniques.

In this work, novel supports with the potential to combine and expand the application of open tubes and regular array columns to preparative chromatography will be presented. These new stationary phases, inspired by the human intestine and partially made by means of addictive manufacturing, consist in a regular array of conduits in which the mobile phase flows. Several columns, that differ in conduits shape and dimension and fluid distributor design, have been manufactured. To overcome the limitations related to the employed material and to increase the surface area, the conduits surface was coated with nanofibrillated cellulose (NFC) dispersed in acetone by deep or spray coating, depending on the columns shape and design. Several NFC concentrations in acetone were tested, ranging from 0.1% to 2% wt/v. The morphology of the cellulose coating was verified by SEM analysis and its adhesion was tested after several chromatographic cycles at process operative conditions. The cellulose was functionalized using Cibacron Blue as a model ligand and bovine serum albumin (BSA) was used as target molecule in affinity chromatographic cycles, performed at several flow rates and BSA concentrations, to determine the highest dynamic binding capacity (DBC) of the support. In addition, the columns were completely characterized for their fluid dynamic performances, in terms of height equivalent to a theoretical plate (HETP) and asymmetry factor. The result obtained were encouraging, showing promising performance and moderate pressure drops even at high flow rates, making possible to significantly extend the column length to increase the surface area and for scaling up purposes. A critical approach will present and analyze this technology that has the potential to significantly improve the efficiency of preparative chromatographic separations.