An Amperometric Biosensor for Glucose Based on a Composite Electrode of Glucose Dehydrogenase, Carbon Nanotubes, and Plasma-polymerized Thin Films

Abstract

We report on an amperometric biosensor that is based on a nanocomposite of carbon nanotubes (CNT), a nano-thin plasma-polymerized film (PPF), and glucose dehydrogenase (GDH). A mixture of the GDH and a CNT film is sandwiched with 6-nm-thick acetonitrile PPFs. Under PPF layer was deposited onto a sputtered gold electrode. To facilitate the electrochemical communication between the CNT layer and GDH, CNT was treated with nitrogen plasma. The resulting device showed that the large oxidizing current response due to enzymatic reaction was observed at +0.4 V (vs. Ag/AgCl) polarized potential. This demonstrates that the CNT play a role as a catalysis for NADH oxidation caused by enzymatic reaction and as a electron transfer conductor. The optimized glucose biosensor showed sensitivity of 3.3 µA mM⁻¹ cm⁻² (correlation coefficient of 0.983, linear response range of 4.9–19 mM) and response of 7 s (reach 95% of maximum response).