An Imperata Cylindrical Flowers-Shaped Porous Graphene Microelectrode for Direct Electrochemistry of Glucose Oxidase

Abstract

A novel flowers-shaped porous active graphene microelectrode has been fabricated by directly electrochemical assembly and reduction of graphene oxide on platinum (Pt) wire with a diameter of 250 μm. The flowers-shaped graphene microelectrode was characterized by SEM, XRD and electrochemical techniques. Results showed that the flowers-shaped graphene microelectrode created a favorable microenvironment for the GOD. The as prepared graphene microelectrode exhibited excellent electron transfer properties for GOD with the rate constant (k s ) of 2.18 s −1 and achieved the direct electrochemistry of GOD. It is notable that the glucose biosensor of GOD@flowers-shaped graphene microelectrode showed two linear ranges in 8.0-148.0 μM with the sensitivity of 267.34 μA mM −1 cm −2 and in 148.0-430.6 μM with the sensitivity of 38.15 μA mM −1 cm −2 for detecting glucose. Furthermore, the biosensor possessed strong anti-interference, remarkable stability and appreciable reproducibility for the sensitive determination of glucose. It would also be extended to other analogous enzymes and bioactive molecules for various biological and electrochemical applications.Diabetes mellitus is a prevalent public health problem and has a great harm on human health in the world. 1,2 Currently, biosensor has become an important testing tool for glucose levels due to its good selectivity and sensitivity. 3 Glucose oxidase (GOD), a structurally rigid oxidoreductase, has been commonly used to construct glucose biosensor. Since the flavin adenine dinucleotide (FAD), a redox active center of the GOD molecule, is deeply embedded within a protective protein shell, it is quite difficult to achieve direct electron transfer (DET) of between GOD and the electrode surface. 4 So many different kinds of materials including porous materials, 5 carbon nanotubes, 6 conductive polymers, 7 gold nanoparticles 8 and graphene 9 have already been studied to improve the DET of between GOD and electrode.In recent years, microelectrode has received special attention in many fields of analytical chemistry 10-12 because of its unique advantages compared with normal electrodes, including smaller size, decreased IR drop, rapid response time, enhanced mass transport and increased signal-to-noise ratio. 13,14 On the other hand, small size of microelectrode can monitor substances timely, continuously and noninvasively in vivo and in vitro. In our previous work done by Huang and Cui,15,16 graphene has been used for the construction of normal electrodes on account of the good conductivity and unique biological compatibility. However, the limited active surface area and severe loss of electroactive sites of two-dimensional (2D) structure prompts us to have to develop a new three-dimensional (3D) electrode. Some efforts have been made to construct the 3D structure electrodes, including 3D graphene foam, 17 3D graphene modified electrode 16 and so on. In this work, due to the fragile nature of freestanding 3D graphene, platinum (Pt) wire which possessed excellent conductivity, fav...

Porous Inorganic Materials for Bioanalysis and Diagnostic Applications

“…Shi et al further pushed this field forward, by fabricating a flower-like porous graphene-based microelectrode for real-time in vivo monitoring of glucose. The device enabled superior linear ranges of 8–430.6 μM and low LOD of 1 μM, due to excellent direct electron transfer properties of the porous materials . Recently, disposable and portable sensing strips were developed for point-of-care measurements of glucose, based on a highly porous graphene electrode .…”

“…The device enabled superior linear ranges of 8−430.6 μM and low LOD of 1 μM, due to excellent direct electron transfer properties of the porous materials. 138 Recently, disposable and portable sensing strips were developed for point-of-care measurements of glucose, based on a highly porous graphene electrode. 139 As a result, a broad linear range of 10 μM to 10 mM with a LOD of 6.3 μM was observed using the costeffective testing strips.…”

The Hydrogen-Bonded Ferrocenylmethanol: Mediation of Electron Transfer for Physically Adsorbed Glucose Oxidase

“…6 As a result, a lot of mediators are introduced to improve electron transfer through the blocking SAMs, such as 1,10-phenanthroline derivatives, 7 ferrocene derivatives, 8 CNTs and graphene. 9 It has been realized that mediators in solution is valid for ET mediation. However, the mediation efficiency of mediators in solution is usually not quite as well as the mediators immobilized on the electrode surface.…”

Synthesis of PtNPs/MWCNT Functionalized with 4-Mercaptophenylboronic Acid for an Electrochemical Sensor of Fructose

“…[5][6][7] Therefore the detection and quantification of fructose and carbohydrates using practical methods are very important. Many studies are being made in this field employing glucose-oxidase 8,9 and d-fructose dehydrogenase 10,11 for glucose and fructose determination respectively. The enzymatic sensors show low detection limits, high sensitivity and selectivity, but the most serious problem with this type of sensors is the lack of stability due to the intrinsic nature of the enzyme.…”