There were practical limitations in using the pressure-flow technique alone to for mechanical characterisation, including the large quantity of chromatography resin and buffers and the stringent criteria required to pack a column. The results showed that the Capto family had the highest critical velocities (Capto Adhere- 492, Capto Q- 477 cm/hr), whilst Sepharose CL-6B, Sepharose 4 Fast Flow and Sepharose CL-4B had the lowest critical velocity values (283, 204, 149 cm/hr respectively). Scanning electron microscopy (SEM) was used to image the structural properties of nine widely used agarose-based chromatography resins before use while pressure-flow analysis was used to characterise the mechanical properties of the same fresh resins. By understanding this, there is significant potential for facilitating timely and improved decisions in large-scale chromatographic operations, maximising resin lifetime whist maintaining acceptable column performance. This thesis, completed in collaboration with Eli Lilly & Co., aims to understand and assess the structural and mechanical changes that occur as agarose-based chromatography resins are exposed to different bioprocessing conditions in an attempt to explore the mechanisms by which different resins age.

Capto resin