Ionic hydrophilic high molecular weight redox polymers for use in enzymatic electrochemical-based sensors include a hydrophilic polymer (such as a hydrophilic polymer backbone) with ionic portions (e.g., cationic monomers incorporated in the hydrophilic polymer backbone) and a plurality of attached redox mediators. The redox mediators can be, for example, covalently attached to the hydrophilic polymer in a pendant manner. An exemplary cationic hydrophilic high molecular weight redox polymer is synthesized by co-polymerization of a hydrophilic acrylamide monomer, [2-(acryloyloxy)ethyl]trimethyl ammonium chloride and vinyl ferrocene.