US Patent 7153426 Charged filtration membranes and uses therefor

The invention relates to charged filtration membranes and their use for separation of a protein from solvent, low molecular weight solutes or a mixture of proteins. Modification of the membranes to generate charge includes modification of membrane pores to alter charge within a pore and alter the size of a pore. Consequently, the protein is separated from other solutes in a mixture based on size as well as net protein charge and membrane charge.