Embodiments of the present disclosure describe functionalized polymeric membranes including one or more dithiol compounds that extend from a nanoparticle provided on or near a surface and/or pores of a polymer material, wherein at least one thiol of the dithiol compound binds to the nanoparticle and at least one thiol of the dithiol compound is a free thiol. Embodiments of the present disclosure further describe methods of separating and/or recovering a purified antibody comprising contacting a feed stream containing an antibody and other biomolecules with a functionalized polymeric membrane to separate the antibody from the feed stream; and applying a reducing agent to release the antibody from the membrane and recover a purified antibody; wherein the functionalized polymeric membrane includes a plurality of free thiols selective to binding the antibody.