The present invention is directed to a method of producing a substrate suitable for separation of a target molecule from a fluid medium. This method includes providing an emulsion comprising a water phase in an oil phase, where the oil phase contains a polymerizable monomer and the water phase contains the target molecule. The substrate, having pores extending from one side of the substrate to another side of the substrate, is coated with the emulsion, and the monomer in the emulsion coated substrate is then polymerized. The water and target molecule are removed from the polymerized, emulsion coated substrate. As a result, the substrate is imprinted with the target molecule and, therefore, is suitable for separation of the target molecule from a fluid medium. The resulting article and its use are also disclosed.