Effect of Pore Structure on Protein Capacity in Macroporous Polymer Chromatographic Supports

Macroporous microspheres were prepared through suspension polymerization, based on a copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate , which were used for functional monomer and crosslinking agent, respectively. The effect of porogen on microspheres structure was evaluated in terms of pore size and surface area. The anion exchanged supports were prepared through derivation of microspheres with poly ( ethylene imine). The relation of the microspheres structure and the protein capacity was examined on these anion exchanged media. The results indicated that the pore size of microspheres increased with the poor solvent in the porogen ( good solvent/poor solvent = 1 : 1-1 : 3. 5 ) , however, the surface area showed a contrary trend. The ion exchanged capacity ( 0. 11-0. 27 mmol/mL) increased with the surface area of the microspheres (4-38 m(2)/g) , and the responding static binding capacity of proteins also show a positive correlation with the surface area. The dynamic binding capacity of proteins firstly increased and then retained a changeless value in the pore range of 301-1524 nm. This value was retained at 13 mg/mL when the pore size was more than 410 nm. It indicated that the surface area could not influence the dynamic binding capacity while the pore size of media was beyond some value. Furthermore, the large biomolecular transport in the microspheres was observed through laser scanning confocal microscopy. The results indicated that hepatitis B virus surface antigen ( HBsAg) could enter freely the microsphere with all of above pore size. The above results provide a reference for fabrication of the chromatographic supports.