Multi-walled carbon nanotubes-based glucose biosensor prepared by a layer-by-layer technique

The loading of multi-walled carbon nanotubes (MWNTs) and glucose oxidase (GOx) in the alternate layers of a glucose biosensor was first optimized based on a layer-by-layer construction on the surface of a graphite disk electrode. With the increasing of MWNTs/GOx layers, the response current to glucose was changed regularly and the response current reached a maximum value when the number of MWNTs/GOx layers was 6. Owing to a good electrical conductivity, strong adsorption and excellent bioconsistency of MWNTs, the (MWNTs/GOx) ₆ films-coated glucose biosensor had an excellent electrochemical properties. The response current of the (MWNTs/GOx)₆ films-coated biosensor to 3 × 10^{- 2} M glucose was 1.63 μA while the response time was only 6.7 s. The linear range and the lowest detectable concentration of this biosensor was 5 × 10^{- 4}∼1.5 × 10^{- 2} M and 0.9 × 10^{- 4} M, respectively.