Abstract: A regenerable support matrix useful for immobilization of biologically active materials is prepared by coating a core support with a cellulose ester, removing ester groups by hydrolysis to produce hydroxyl groups and converting the hydroxyl groups to dialkylaminoalkyl ether groups. The support matrix can immobilize biologically active proteinaceous materials with a net negative charge by adsorption. The support matrix is readily regenerated when an immobilized biologically active material becomes inactive by washing the support with a base or salt solution and adsorbing additional biologically active material to the support. Multiple cycles of immobilization and regeneration are possible without significant deleterious affects.