"Volume or mass and viscoelastic changes in Os(byp)2ClPyCH2NH2\u2212poly(allylamine) hydrogel (Os\u2212PAA)cross-linked with glucose oxidase (GOx), have been measured by studying the electroacoustic impedance at10 MHz. Film thickness and shear modulus have been obtained from imaginary and real components of theEQCM acoustic impedance in transient (cyclic voltammetry and chronoamperometry) as well as steady stateoxidation and reduction of the hydrogel. Swelling of the film during OsII oxidation resulted in mass uptakeand decrease of shear modulus. These quantities depend only on the degree of polymer oxidation and not onfilm history or kinetics. Gravimetry beyond the Sauerbrey mass limit could be realized by use of Martin'sviscoelastic model to treat the quartz crystal impedance." . . . . . . . . . . . . . "Viscoelastic Changes in Os-Containing Poly(allylamine) Based Redox Hydrogels forAmperometric Enzyme Electrodes: An EQCM Study" .