Briefly, a sensor for a continuous biological monitor is provided that has a working electrode with a new interfere layer that is (1) non-electron conducting, (2) ion passing, and (3) permselective for molecular weight. The new interference layer is made by mixing a monomer and a mildly basic buffer, and then electropolymerizing the monomer and the buffer into a polymer. The polymer is deposited onto a working electrode for a continuous metabolic monitor, for example, using an electro depositing process in the form of cyclic voltammety (CV). The interference layer is permselectable for molecule size by adjusting the pH of the basic buffer.
