Preparation, characterization, and process performance of composite fibrous adsorbents as cation exchangers for high throughput and high capacity bioseparations

Fibrous materials are proposed as novel chromatographic supports depicting high throughput and high product capacity. In this work, a composite fiber harboring strong cation-exchange moieties has been investigated. Such materials were characterized by a plethora of physical methods including degree of swelling (DS), scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM), and Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR). The composite showed a high degree of grafting (similar to 30%) and exhibited a high swelling ratio (similar to 300%). Moreover, homogenous grafting and the development of an internal (functional) hydrogel were observed. The fibrous adsorbent was packed utilizing a designed "double roll" supported-structure and subsequently tested for packing efficiency and chromatography performance. The mentioned system showed similar packing efficiency of height equivalent to a theoretical plate (HETP) value and higher permeability coefficient (0.92 x 10(-7) cm(2)) than commercial resins. Experimentally determined Peclet number (Pe) values were within the range 60-90, suggesting a close-to-plug-flow condition. Total ionic capacity of the fibrous adsorbent was determined by the transition pH method. A capacity of 6.5 mequiv./g was obtained. Moreover, a high dynamic binding capacity for lysozyme was found to be 283 mg/g. On the other hand, a bed of randomly packed fiber also demonstrated high-resolution ability when a mixture of model protein was utilized to that end. Resolution was maintained at high flow rates (up to 900 cm/h) and utilizing shorter gradient development routines. Direct sequestration of a model protein (lysozyme) was also possible from an artificial mixture containing 1.5% yeast homogenate. Summarizing, the composite fibrous adsorbents exhibited superior performance during early protein capture and intermediate-resolution applications. (C) 2012 Published by Elsevier B.V.