Electrochemical determination of sugars by use of multilayer thin films of ferrocene-appended glycogen and concanavalin A

Multilayer thin films containing concanavalin A (Con A) and ferrocene-appended glycogen (FcGly) were prepared by a layer-by-layer deposition Con A and FcGly by biological affinity (lectin–sugar interaction) on a glassy-carbon electrode. The electrochemical response of the Con A–FcGly film-coated electrode to sugars was investigated. A cyclic voltammogram (CV), typical of redox species confined to the surface of the electrode, was obtained. The peak current (resulting from the electric charge involved in the redox reaction) in the CV from the electrode decreased on addition of sugars in the solution, because the amount of FcGly on the electrode surface decreased as a result of disintegration of the Con A–FcGly film on addition of sugar. Thus, d-glucose and other sugars at millimole per liter levels can be detected by use of Con A–FcGly films-coated electrodes.