Short communication
Fabrication of ultra-sensitive and selective dopamine electrochemical sensor based on molecularly imprinted polymer modified graphene@carbon nanotube foam

https://doi.org/10.1016/j.elecom.2016.01.009Get rights and content

Highlights

  • Graphene@carbon nanotube foam combined with MIP as a novel supportless sensor

  • Modification of MIP was confirmed and its key role in sensing target was studied.

  • The 3D free-standing electrode proves its outstanding performance in dopamine assay.

  • Ultralow detection limit and wide range were achieved with the hybrid sensor.

Abstract

A new type of three-dimensional (3D) electrochemical sensor was prepared by combining carbon nanotubes on graphene foam (GF/CNT) with molecularly imprinted polymer (MIP), which affords simultaneous identification and quantification towards target compound. The hybrid sensor shows ultralow detection limit of 6.67 × 10 16 M (S/N = 3), wide range of 2 × 10 15 M to 1 × 10 12 M, and superb selectivity for dopamine (DA) detection.

Introduction

High sensitivity, among others, is one featured merit of electrochemical sensor in quantification of substances [1], [2], [3], [4], [5], [6]. However, target analyte possessing electrochemical activity is a prerequisite of this approach as most of electrochemical determination is based on redox reaction of analyte on the interface between electrode and electrolyte [7], [8], [9]. One way to circumvent this requirement is to cover the electrode surface with a non-conductive membrane which owns on/off gates in response to analyte and apply probe media to indicate electrical signals. Thereafter, concentration of target molecules can be calculated. By carefully molding the gates on the membrane, selective recognition of sensor toward targets can also be realized.

Our groups, as well as others, have developed such a sensing strategy by using molecularly imprinted polymer (MIP) as the insulating film [10], [11], [12], [13], [14], [15], [16], where commercial electrodes are often adopted. Besides, in these reports, additional materials with good conductivity and high surface area are usually involved in order to enhance sensitivity and electron transfer rate [14], [15], [16], [17]. Recently, we fabricated gold microwire with nanoporous surface as supportless working electrode and used it for accurate, sensitive and selective assay of metronidazole [18]. With the aim of exploring sensing materials with more desirable performance, we turn to the widely distributed element-carbon, and employed three dimensional (3D) carbon nanotube at graphene foam as the electrode substrate. Preparation of such hybrid materials have been reported [19], [20] and they are mainly applied as high-performance energy storage devices [21], [22]. Herein, we construct a novel electrode by coupling the carbon hybrid with MIP film and this free-standing sensor proves its outstanding performance in dopamine (DA) detection.

Section snippets

Reagents and apparatus

Dopamine (DA), ascorbic acid (AA) and uric acid (UA) were purchased from Adamas Reagent Co. Ltd. (Shanghai, China). L-adrenaline bitartrate (AD), o-phenylenediamine and α-phenylethylamine (PEA) were from Sigma-Aldrich Co. (Shanghai, China) and phosphate buffer solution (PBS) was prepared from KH2PO4 and K2HPO4. 3-O-methyldopamine hydrochloride and caffeic acid were obtained from Adamas Reagent Co. Ltd. All the reagents are of analytical grade and the solutions were prepared with double

Results and discussion

Typical cyclic voltammograms during MIP preparation are displayed in Fig. 1A. The currents decreased with continuous scanning until no more changes can be observed at the last several cycles, suggesting that an insulating polymeric film formed on GF/CNT and led to restraint of the voltammetric response. In Fig. 1B, the Raman spectrum of GF illustrates two characteristic peaks at ~ 1584 cm 1 (G-band) and ~ 2726 cm 1 (2D-band) [5], [23], and the G/2D ratio suggests typical graphene structure with

Conclusion

We demonstrate the use of GF/CNT/MIP as a novel supportless (free of using any commercial working electrode) electrochemical sensor, which displayed excellent sensing performance in detecting DA. The superb sensitivity may stem from (1) large surface area of the 3D skeleton and the densely aligned CNT, and (2) high conductivity of the multiplexed conductive pathways of GF/CNT, while the good selectivity and anti-interference capability are ensured by the MIP film. Besides, the sensor features

Conflict of interest

There are no conflicts of interest.

Acknowledgments

The project was financially supported by the Major Program for Science and Technology Development of Shihezi University (gxjs2014-zdgg04), the National Natural Science Foundation of China (81260487, 81460543, 21575089), the Scientific Research Foundation for the Returned Overseas Chinese Scholars from Ministry of Human Resources and Social Security of China (RSLX201301), and the Pairing Program of Shihezi University with Eminent Scholar in Elite University (SDJDZ201502). The authors thank

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