A method of binding a target molecule from an analyte containing the target molecule in admixture with at least one non-target molecule, which method comprises exposing the analyte to a substrate comprising first and second surface binding components, wherein the first surface binding component has specific binding affinity with respect to the target molecule but is independently unable to provide effective binding of the target molecule to the substrate, wherein the second surface binding component has non-specific binding affinity with respect to the target molecule and is independently unable to provide effective specific binding of the target molecule to the substrate, and wherein the target molecule is immobilized on the substrate by the combined binding effect of the first and second surface binding components.