Electrochemical study of mono-6-thio-beta-cyclodextrin/ferrocene capped on gold nanoparticles: characterization and application to the design of glucose amperometric biosensor.

A novel amperometric glucose sensor based on inclusion complex of mono-6-thio-beta-cyclodextrin/ferrocene capped on gold nanoparticles (GNPs/CD-Fc) and glucose oxidase (GOD) was described. The inclusion complex of mono-6-thio-beta-cyclodextrin/ferrocene capped on gold nanoparticles played an effective role of an electron shuttle and allowed the detection of glucose at 0.25 V (versus SCE), with dramatically reduced interference from easily oxidizable constituents. The sensor (GNPs/CD-Fc/GOD) showed a relatively fast response time (5 s), low detection limit (15 microM, S/N=3), and high sensitivity (ca. 18.2 mA M(-1) cm(-2)) with a linear range of 0.08-11.5mM of glucose. The excellent sensitivity was possibly attributed to the presence of the GNPs/CD-Fc film that can provide a convenient electron tunneling between the protein and the electrode. In addition, the biosensor demonstrated high anti-interference ability, stability and natural life. The good stability and natural life can be attributed to the following two aspects: on the one hand, the fabrication process was mild and no damage was made on the enzyme molecule, on the other hand, the GNPs possessed good biocompatibility that could retain the bioactivity of the enzyme molecules immobilized on the electrode.