Carbon nanotubes non-covalently functionalized with cytochrome c: A new bioanalytical platform for building bienzymatic biosensors

Abstract

We report for the first time the use of glassy carbon electrodes (GCE) modified by drop-coating with multi-walled carbon nanotubes (MWCNTs) dispersed in cytochrome c as platform for the construction of bienzymatic biosensors, using the glycoenzyme glucose oxidase (GOx) as model. The sensitivity of the resulting biosensor at -0.050 V towards glucose using hydroquinone (H(2)Q) as redox mediator was (96 +/- 2) mu A M-1, with a linear range between 1.00 x 10(-4) M and 1.00 x 10(-3) M and a detection limit of 8 mu M. The biosensor demonstrated to be highly reproducible with RSD. values of 6.1% for five different bioelectrodes. The combination of the excellent dispersing properties of Cyt c, the stability of MWCNTs-Cyt c dispersion and the intimate interaction between Cyt c, MWCNTs and GOx, allowed the construction of an efficient glucose biosensor successfully used to determine glucose in commercial beverages. (C) 2016 Elsevier B.V. All rights reserved