There is provided a selectively permeable biointerface membrane, permitting selective diffusion of analyte therethrough, for use in an analyte sensor comprising a nanoporous substrate and a coating, on the nanoporous substrate, comprising a plurality of polymer chains whereby each polymer chain is attached at one chain end thereof to a surface of the nanoporous substrate. There are also provided methods for the preparation of the selectively permeable membrane and an analyte sensor comprising the membrane.