The invention relates generally to methodsof concentrating mixtures including shear sensitivebiopolymers, such as von Willebrand Factor. Conventionalmethods of concentrating biopolymers impart too muchshear stress, which causes the degradation of shearsensitive biopolymers. The methods disclosed herein reducethe shear stress while maintaining a high rate of filtrateflux. Disclosed herein is a method for concentrating shearsensitive biopolymers including flowing a mixture with ashear sensitive biopolymer into a hollow fiber dialysismodule to form a retentate having a shear sensitivebiopolymer concentration that is greater than that of themixture. Hollow fiber dialysis modules have high filtratefluxes and low shear rates at low flow rates. This ensuresa high product yield and minimal loss of shear sensitivebiopolymers.
