(313g) High Affinity Membrane Adsorbers for Protein Purification

Specific protein-substrate recognition is critical for developing high affinity chromatography for protein purification. It provides an effective strategy to separate different proteins that have similar size and charge but different surface amino acid residues. Applying this molecular recognition strategy to modify membrane surface is promising to generate high performance membrane adsorbers for protein purification. Our work focuses on grafting a new polymer based ligand from the regenerated cellulose membrane (0.45μm pore size) surface by atom transfer radical polymerization (ATRP). Bisphosphonate was used as the functional monomer since it has a remarkable affinity to arginine residue. Other hydrophilic monomer such as N-(2-hydroxypropyl) methacrylamide (HPMA) and  D-gluconamidoethyl methacrylate (GAMA)  were used as the spacer monomer to enhance the flexibility of the polymer ligand and reduce the non-specific binding due to hydrophobic interaction. The copolymerization of bisphosphonate and the spacer monomers using ATRP was successfully achieved. Static and dynamic binding capacities were determined for the Arg rich Lysozyme and compared with other model proteins including BSA and IgG. The mechanism for the specific binding was explored using classical molecular dynamics simulations.