In search of suitable matrices for enzyme im-
mobilization, there has been a growing interest in
attaching the enzymes to the solid electrolyte Na-
fion. The Nafion membrane possesses a high sur-
face adhesion property and a low swelling capa-
bility in aqueous media. Being a negatively
charged polyelectrolyte matrix, Nafion exhibits a
reduced permeability to negatively charged sub-
stances, therefore improving the sensor selectiv-
ity and virtually eliminating the interference of
reductants such as ascorbate and acetaminophen.
On the other hand, a Nafion film possesses a high
ability to entrap positively charged redox-active
compounds that can be used as mediators in bio-
electrocatalytic reactions. In addition, the poly-
electrolyte nature of the Nafion film can stabilize
the ionic strength at the electrode surface,
thereby preventing electrode fouling and increas-
ing the dynamic range for analyte detection.