Biocomposites of covalently linked glucose oxidase on carbon nanotubes for glucose biosensor

Abstract

The formation of covalently linked composites of multi-walled carbon nanotubes (MWCNT) and glucose oxidase (GOD) with high-function density for use as a biosensing interface is described. The reaction intermediates and the final product were characterized by using FT-IR spectroscopy, and the MWCNT-coated GOD nanocomposites were examined by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Interestingly, it was found that the GOD-MWCNT composites are highly water soluble. Electrochemical characterization of the GOD-MWCNT composites that were modified on a glassy carbon electrode shows that the covalently linked GOD retains its bioactivity and can specifically catalyze the oxidation of glucose. The oxidation current shows a linear dependence on the glucose concentration in the solution in the range of 0.5-40 mM with a detection limit of 30 microM and a detection sensitivity of 11.3 microA/mMcm2. The present method may provide a way to synthesize MWCNT related composites with other biomolecules and for the construction of enzymatic reaction-based biofuel cells and biosensors.

Chemically Modified Carbon Nanotubes: Derivatization and Their Applications

“…The conjugated monolayer of nanotube cyctochrome C (Cyt C) were prepared and stabilized at air-water interface. The electrochemical measurements showed well resolved redox peaks for modified Cyt C when compared to pure Cyt C due to the fact that the fast electron transfer takes place at the nanotube supports [96]. An amperometric third generation H 2 O 2 biosensor based on the immobilization of hemoglobin on MWCNTs and gold colloidal nanoparticles has been reported [97].…”

Mediated Biocatalytic Electrodes and Enzyme Stabilisation for Power Generation

“…The functionalisation of MWNTs with biopolymers of cellulose derivatives and the study of the direct electron transfer of multicopper oxidades, such as laccase, and bilyrubin oxidase, yielded promising results in ascorbate/ O 2 -based biofuel cells [66]. Covalently linked composites (MWCNT) and glucose oxidase [67] or chitosan [68] with high-function density have also been described.…”

“…A variety of approaches have Review P. Brito, A. P. F. Turner been used to immobilise enzymes onto electrode surfaces including absorption, covalent linkage, enzyme entrapment or encapsulation [25]. Common approaches are adsorbing the enzymes onto conductive particles such as carbon black or graphite powder [26,27], entrapping them in polymeric matrices [28], the use of redox polymers [18], co-immobilisation of cofactor-mediator complexes on metal electrodes [25], enzyme incorporation onto nanostructured magnetic materials [29] and the use of carbon nanotubes [30] and silica-based nanostructures [31]. Semi-permeable membranes are advantageous for entrapment when diffusional mediators are used since these prevent flux of mediator species out of the electrode, but they also limit the diffusional flux of reactants into and products out of the electrode.…”

Biosensors and Their Principles

“…The first alternative is the SWCNT which was deposited on bare glassy carbon electrode (GCE) and then hydrogel containing the redox polymer and the enzyme for catalytic effect. Second alternative is SWCNT which were developed with enzyme solution after this process it was treat redox hydrogel and then modify with GCE [26,[48][49]. (Fig.…”