Highly sensitive glucose oxidase (GOD) electrodes were fabricated on the basis of microstructured polypyrrole (PPy) films. The microstructures of the PPy films had a morphology like cups and 2 were arranged in a density of approximately 4000 units/cm(2). GOD was immobilized in microstructured PPy films coated on a Pt or stainless steel (SS; AISI 321) substrate electrode. The GOD/PPy/Pt electrode showed a linear response to glucose concentrations in the range of 0-17 mM at a potential of 0.4 V (vs a saturated calomel electrode). Its sensitivity was measured to be approximately 660 nA/(mM cm(2)) at 15 degrees C, and the response time (t(95%)) was approximately 20 s. In comparison, the sensitivity of the GOD/PPy/Pt electrode based on a flat PPy film was only approximately 330 nA/(mM cm(2)) under the same conditions. The sensitivity of the microstructured GOD/PPy/Pt electrode could be increased to as high as approximately 2400 nA/(mM cm(2)) at 37 degrees C. The microstructured GOD/PPy/SS electrode had a sensitivity of approximately 550 nA/(mM cm(2)) and a t(95%) value of approximately 30 s at 15 degrees C and 0.4 V. (c) 2005 Wiley Periodicals, Inc.