Carbon Microstructures for Glucose Biosensor
H. Xu, K. Malladi, C. Wang and M.J. Madou
University of California, Irvine, US
glucose sensor, C-MEMS, conducting polymer, polypyrrole
In this work we report on a novel design and fabrication of glucose sensor based on carbon post electrode array. Apart from the fact that carbon has a wide electrochemical stability window, one advantage of using carbon post as working electrode for the amperometric glucose sensor is its high surface to volume ratio, greatly improving sensitivity of glucose sensor consequently. These carbon microstructures on a carbon substrate are about 50μm in diameter and every two adjacent posts are 50μm apart. Glucose oxidize (GOD) is immobilized by electrochemical polymerization of polypyrrole (PPy) of 5μm in thickness on those carbon posts. Glucose sensing performance for 100μm high carbon post on carbon film, 25μm high carbon post on carbon film, carbon film without posts and gold film were tested and compared. The result illustrates a linear range of glucose concentration (20mmol/L) and demonstrates larger sensitivity with higher posts, which could be explained by more reaction sites of GOD/glucose due to their larger surface area. Sensitivity of glucose sensor on gold film is larger than that of carbon film without any posts, however, its sensitivity is one order of magnitude smaller than that of carbon film electrode with high carbon posts.
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Nanotech 2006 Conference Program Abstract