The invention relates generally to methods of concentrating mixtures including shear sensitive biopolymers, such as von Willebrand Factor. Conventional methods of concentrating biopolymers impart too much shear stress, which causes the degradation of shear sensitive biopolymers. The methods disclosed herein reduce the shear stress while maintaining a high rate of filtrate flux. Disclosed herein is a method for concentrating shear sensitive biopolymers including flowing a mixture with a shear sensitive biopolymer into a hollow fiber dialysis module to form a retentate having a shear sensitive biopolymer concentration that is greater than that of the mixture. Hollow fiber dialysis modules have high filtrate fluxes and low shear rates at low flow rates. This ensures a high product yield and minimal loss of shear sensitive biopolymers.
