Graphene versus Multi-Walled Carbon Nanotubes for Electrochemical Glucose Biosensing

Abstract

A simple procedure was developed for the fabrication of electrochemical glucose biosensors using glucose oxidase (GOx), with graphene or multi-walled carbon nanotubes (MWCNTs). Graphene and MWCNTs were dispersed in 0.25% 3-aminopropyltriethoxysilane (APTES) and drop cast on 1% KOH-pre-treated glassy carbon electrodes (GCEs). The EDC (1-ethyl-(3-dimethylaminopropyl) carbodiimide)-activated GOx was then bound covalently on the graphene- or MWCNT-modified GCE. Both the graphene- and MWCNT-based biosensors detected the entire pathophysiological range of blood glucose in humans, 1.4–27.9 mM. However, the direct electron transfer (DET) between GOx and the modified GCE’s surface was only observed for the MWCNT-based biosensor. The MWCNT-based glucose biosensor also provided over a four-fold higher current signal than its graphene counterpart. Several interfering substances, including drug metabolites, provoked negligible interference at pathological levels for both the MWCNT- and graphene-based biosensors. However, the former was more prone to interfering substances and drug metabolites at extremely pathological concentrations than its graphene counterpart.

Immobilization of Antibodies and Enzymes on 3-Aminopropyltriethoxysilane-Functionalized Bioanalytical Platforms for Biosensors and Diagnostics

“…231,232 Various electrode materials may influence critical factors for increased biosensor detection limits such as the efficiency of direct electron transfer, molecular recognition, enzyme matrix distribution, or stability. The application of APTES in layer-by-layer (LbL) and SAM, 111,112,[218][219][220][221][222]233 sol− gel, 173,174 or electrodeposited systems [223][224][225]234 resulted in different 2D and 3D structures that significantly improve the performance of electrochemical glucose biosensors. The most commonly used APTES-based electrochemical sensing techniques are steady-state amperometry at a fixed detecting potential in mediatorless sensing, 112,174,175,219,220,224,226−230 DPV in redox detection of ferrocene-tagged Ab, 232 and electrochemical impedance spectroscopy.…”

“…The same concept was extended for the detection of human IgG with a LOD of 40 ng mL −1 using a sol−gel derived amorphous BST thin film and a highly diluted NaCl solution as electrolyte. and graphene/MWCNT-functionalized GCE 112 have been employed for mediatorless electrochemical glucose sensing. While both GCEs can detect the entire pathophysiological glucose range of blood glucose, the graphene/MWCNTfunctionalized GCE exhibits a 4-fold higher current signal due to DET.…”

“…111 This strategy is also applicable for covalent immobilization of GOx on a graphene-functionalized GCE. 112 The GCE pretreated with 1% KOH is allowed to react with graphene (1 mg mL −1 dispersed in 0.125% APTES). APTES plays a dual role in this procedure, acting as a surface modification agent that introduces amino groups on the GCE and graphene, besides its role as a dispersion agent.…”

Biosensors Based on Lipid Modified Graphene Microelectrodes

“…The advantages of graphene are as follows: graphene exhibits the advantages of a large surface area (2630 m 2 ·g −1 for single-layer graphene), similar to that of carbon nanotubes (CNTs) [12], and a small size of each individual unit. It also exhibits some other merits like low cost, two external surfaces, facile fabrication and modification and absence of metallic impurities, which may yield unexpected and uncontrolled electrocatalytic effects and toxicological hazards [7,10,11].…”

Electroanalytical Measurement of TEDA (Triethylenediamine) in the Masks of War

“…Among all of the carbon electrodes, the carbon paste electrode (CPE) is an appealing and widely used electrode in the fields of electrochemistry and electroanalysis due to simple preparation, low-cost implementation and renewability [6,7]. Graphene electrodes have shown superior performance in terms of electrocatalytic activity and macroscopic scale conductivity than glassy carbon, graphite and even carbon nano tube electrodes [3,8,9]. The modified graphene carbon paste electrodes have been successfully applied to study and measurement some biological and organic molecules [10].…”