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.
Highlights
Graphene has been widely used for the development of optoelectronic devices [1], super capacitors [2] and various types of high performance sensors [3,4,5,6,7] due to its high surface-area-to-volume ratio [8,9], excellent electrical conductivity and high electron mobility [10]
carbon nanotubes (CNTs)-based electrodes are compared for various biosensors [32,33,34], and to our knowledge, there is no comparison of graphene- and multi-walled carbon nanotube (MWCNT)-based electrodes for electrochemical glucose biosensing with respect to direct electron transfer
This study describes a simple procedure for the fabrication of the graphene- and MWCNT-based electrochemical glucose biosensors using glucose oxidase (GOx) (Scheme 1)
Summary
Graphene has been widely used for the development of optoelectronic devices [1], super capacitors [2] and various types of high performance sensors [3,4,5,6,7] due to its high surface-area-to-volume ratio [8,9], excellent electrical conductivity and high electron mobility [10]. It is of considerable interest to evaluate if graphene is advantageous compared to carbon nanotubes (CNTs) in various applications; in electrochemical biosensing for glucose, since the latter, with a high surface-volume ratio, has been extensively used in the development of super capacitors [13,14,15], energy storage devices [16], environmental sensing devices [17,18], drug delivery systems [19], biosensors [20,21] and other devices. There are only a few reports where graphene and CNT-based electrodes are compared for various biosensors [32,33,34], and to our knowledge, there is no comparison of graphene- and multi-walled carbon nanotube (MWCNT)-based electrodes for electrochemical glucose biosensing with respect to direct electron transfer. The preparation of graphene- and multi-walled carbon nanotube (MWCNT)-based glucose biosensors
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