Tuesday, November 9, 2010
Hall 1 (Salt Palace Convention Center)
Nonwoven fabrics, with controllable porosity and pore size, relatively high surface area and low cost, have attracted attention as a potential new type of membrane for use in the field of bioseparations. In this work, an anion-exchange nonwoven membrane with high protein binding capacity was successfully prepared using a two-step modification method. Photo-initiated graft polymerization was used to graft a conformal layer of polyglycidyl methacrylate (pGMA) around polybutylene terephthalate (PBT) nonwoven fibers. The epoxy groups present in the glycidyl methacrylate units were then converted to diethylamine (DEA) groups, producing an anion-exchange nonwoven membrane. ATR-FTIR, SEM and XPS were used to characterize the chemical functionality and porous structure morphology before and after each modification step. Bovine serum albumin (BSA) was used to evaluate the protein binding capacity of the modified nonwoven membrane. BSA static binding capacity increased with DEA density and reached a plateau at around 260 mg protein/g membrane when the DEA group density was at 6.0x10-4 mol/g or higher. Determination of BSA binding isotherms also demonstrated the high protein binding capacity of the modified membrane, with a qmax at around 260 mg protein/gram membrane. Static binding capacity of other proteins with pI<7.0 were also determined, yielding values above 220 mg protein/gram membrane for human transferring, â-casein, â-lactoglobulin and ovalbumin. The dynamic BSA binding capacity was achieved around 170 mg protein/gram membrane, which corresponded to 80 mg/ml. Also this high dynamic binding capacity is independent with flow rate.