Direct electrochemical sensing of glucose using glucose oxidase immobilized on functionalized carbon nanotubes via a novel metal chelate-based affinity method

Abstract

We report on a novel amperometric glassy carbon biosensing electrode for glucose. It is based on the immobilization of a highly sensitive glucose oxidase (GOx) by affinity interaction on carbon nanotubes (CNTs) functionalized with iminodiacetic acid and metal chelates. The new technique for immobilization is exploiting the affinity of Co(II) ions to the histidine and cysteine moieties on the surface of GOx. The direct electrochemistry of immobilized GOx revealed that the functionalized CNTs greatly improve the direct electron transfer between GOx and the surface of the electrode to give a pair of well-defined and almost reversible redox peaks and undergoes fast heterogeneous electron transfer with a rate constant (k s ) of 0.59 s −1 . The GOx immobilized in this way fully retained its activity for the oxidation of glucose. The resulting biosensor is capable of detecting glucose at levels as low as 0.01 mM, and has excellent operational stability (with no decrease in the activity of enzyme over a 10 days period). The method of immobilizing GOx is easy and also provides a model technique for potential use with other redox enzymes and proteins.

Graphene–gold nanoparticle composite: Application as a good scaffold for construction of glucose oxidase biosensor

“…Moreover, coupling of amino derivative group of glucose cofactor, Flavin Adenine Dincleotide (FAD), with carboxylic acid moiety has been well defined [10,11,28,33,34]. Of note, the enzyme active sites must be positioned efficiently in close vicinity to the electrode surface for effective electron transfer [31,34].…”

“…4 nanotubes (CNTs), graphene, metal and metal oxide nanoparticles [11,16,[23][24][25][26][27][28][29][30]. It was observed that functionalized surface can affect the immobilization efficiency [31,32].…”

Covalent immobilization of cholesterol oxidase and poly(styrene-co-acrylic acid) magnetic microspheres on polyaniline films for amperometric cholesterol biosensing

“…The value was higher than those of 1.406 Â 10 À8 mol cm À2 at the graphite/functionalized graphene/ChOx; 47 1.96 Â 10 À9 mol cm À2 at the glassy carbon/carbon nanotubes-tridentate iminodiacetic acid-cobalt-glucose oxidase. 48 However, the electroactive ChOx concentration on PANi/Fe 3 O 4 /PSA is lower than the value of the surface concentration of nanoZnO/chitosan which has been found to be 9.02 Â 10 À8 mol cm À2 . 49…”

A strategy for efficient immobilization of laccase and horseradish peroxidase on single‐walled carbon nanotubes

“…Numerous strategies for the immobilization of enzymes on nanomaterials have been described over the years, including the commonly used adsorption, covalent coupling, entrapment and encapsulation. The advantages and disadvantages of each of these strategies have been discussed elsewhere . Bioaffinity‐based enzyme immobilization is an interesting and promising strategy which is mild and has little negative effect on the immobilized enzymes.…”

“…The advantages and disadvantages of each of these strategies have been discussed elsewhere. 22,23 Bioaffinity-based enzyme immobilization is an interesting and promising strategy which is mild and has little negative effect on the immobilized enzymes. Also it allows oriented immobilization of enzyme on a carrier.…”