Controlled nanozeolite-assembled electrode: remarkable enzyme-immobilization ability and high sensitivity as biosensor.

An enzyme-immobilized nanozeolite-assembled electrode was prepared by controlled assembly of nanometer-sized Linder type-L zeolite (nano-LTL-zeolite) on an indium tin oxide (ITO) glass electrode surface, and subsequent immobilization of cytochrome c. Cyclic voltammetric (CV) and amperometric experiments showed that, relative to other reported electrodes, the enzyme-immobilized electrodes possess fast electron-transfer rates (2.2 s(-1)), a broad linear range (15-540 micromol L(-1)), a low detection limit (3.2 nmol L(-1)), a remarkably long lifetime (5 months), and high stability in the pH range 5-10. These characteristics could be due to the fact that nanozeolites assembled on ITO have high immobilization ability and facilitate interaction with enzymes. The function controllability of these enzyme electrodes, resulting from the facile manipulability of nanozeolite-assembled layers, may provide a possibility to rationally design biosensors.