A project is proposed to develop reagents and methods for immobilizing receptors onto polysulfone microporous membranes used for affinity purification, by photoimmobilizing hydrophilic polymeric coupling reagent to which the receptor will then be coupled. The technique is expected to increase the amount of active receptor or antibody molecules. The technology will be developed using a model antibody after which it will also be evaluated for efficiency of immobilizing Staphylococcus aureus Protein A. Use of these methods for preparing affinity membranes is expected to increase the efficiency of the purification process and to reduce the costs of a variety of bioseparations, including purification of recombinant proteins, antibodies and plasma from cell culture supernatants, plasma and ascites fluid.