Elsevier

Talanta

Volume 215, 1 August 2020, 120891
Talanta

NiO@Ni-MOF nanoarrays modified Ti mesh as ultrasensitive electrochemical sensing platform for luteolin detection

https://doi.org/10.1016/j.talanta.2020.120891Get rights and content

Highlights

  • 3D hierarchically porous NiO nanoarray@Ni-MOFs (NiO@Ni-MOFs) was reported.

  • A luteolin electrochemical sensor based on NiO@Ni-MOF was constructed.

  • NiO@Ni-MOF showed ultra-sensitive detection towards luteolin.

  • The method was successfully applied for analysis of luteolin in real samples.

Abstract

A novel electrochemical sensor was constructed based on three-dimensional NiO@Ni-MOF nanoarrays modified Ti mesh (NiO@Ni-MOF/TM). NiO nanoarrays were firstly produced on conductive TM using hydrothermal and carbonization method, and then Ni-MOFs were directly grown on the surface of NiO nanoarrays through self-template strategy. The morphology and structure of the prepared materials were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The as-prepared NiO@Ni-MOF/TM was used as electrochemical sensor for investigating electrochemical behaviors of luteolin flavonoid. The composite electrode combined the excellent enrichment ability of Ni-MOF, high catalysis of NiO nanoarrays with the superior electronic conductivity of TM substrate, enabling ultra-sensitive detection towards luteolin with a low limit of detection (LOD) of 3 pM (S/N = 3). Besides, with favorable stability and selectivity, the fabricated sensor was applied in the determination of luteolin in actual samples with satisfactory results.

Graphical abstract

An ultrasensitive electrochemical sensor based on NiO@Ni-MOF nanoarrays modified Ti mesh was fabricated for luteolin detection.

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Introduction

Luteolin is a representative natural flavonoid [1]. With the deepening of the research, luteolin is found to inhibit the proliferation of cancer cells, induce apoptosis of cancer cells, and enhance the activity of anticancer drugs [2,3]. In addition, luteolin has been used to treat some serious diseases, such as cough, expectoration, inflammation, cardiovascular disease and amyotrophic lateral sclerosis [4,5]. Therefore, the development of a facile and sensitive strategy to detect luteolin has gained growing research attention. At present, various analytical strategies have been established for the quantitative and qualitative detection of luteolin, including spectrophotometry [6], capillary electrophoresis [7], high-performance liquid chromatography [8,9], and electrochemical sensor [10]. Among them, electrochemical sensing technology stands out owing to its fast response, portable feasibility, convenient operation and low cost. Over the past years, some nanomaterials such as Ni/graphene oxide-MWCNTs [11], Au/Pd/reduced graphene oxide [12] modified electrodes have been used for luteolin determination. However, some major problem such as narrow linear range and low sensitivity still remains. Thence, it is necessary to prepare novel electrocatalysts with high catalytic activity.

Metal-organic frameworks (MOFs) are ascendant crystalline porous structural materials with unique features of huge surface area, enormous pore volume as well as easy functionalization [[13], [14], [15]]. Accordingly, MOFs have received great attention as potential electrochemical sensing materials. The high specific surface area and porosity of MOFs increase the concentration and capture of analytes with suitable configuration and size, thus detection signal is amplified [16,17]. In fact, the direct utilization of MOFs in electrochemical sensors is limited for their poor conductivity. Thus, combining MOFs with highly conductive nano-carbon materials including graphene, carbon nanotubes and activated carbon [[18], [19], [20]], is expected to further achieve improved electrochemical performance. However, owing to the weak force between MOFs and these carriers, the obtained MOFs composites usually manifest agglomerated and disordered structure, leading to inferior catalytic ability and poor stability. Therefore, the design of uniform and orderly MOF composites for fabricating high-performance electrochemical biosensors is still urgent.

Self-template strategy based on metal oxide nanostructure is one of the most effective methods for ordered MOFs synthesis [21]. Metal oxide templates offer metal ions at the expense of themselves, and then MOF are directly grown on the surface of metal oxides, forming heterogeneous metal oxides@MOFs. In comparison to pure MOFs, the core-shell MOF heterostructures display great advantages by virtue of their synergism effect. For example, Chen et al. synthesized Fe3O4@MIL-100 (Fe) core-shell composite using Fe3O4 nanosphere as the core [22]. The Fe3O4@MIL-100 modified electrode as electrochemical sensor showed high sensitivity for chlorogenic acid detection with low LOD of 0.05 μM. Zhang et al. reported the utilization of MoO3 nanorods as core for the fabrication of MoO3@ZIF-8 core-shell nanorods [23]. The MoO3@ZIF-8 composite was applied to photocatalytic detection of hexavalent chromium (Cr(VI)) in wastewater. In addition, directly growing electroactive materials on conductive substrates can effectively improve the electron transfer by reducing the contact resistance relative to powder samples assistance with binders [24,25], resulting in significantly improved electrochemical performance. Additionally, different from traditional 2D planar architecture, electrodes with 3D nanoarrays exhibit many inherent advantages in terms of high specific surface area, fast electron transport, and enhanced electrolyte penetration [[26], [27], [28]]. However, the fabrication of NiO@MOF nanoarrays electrode for electrochemical sensing applications has not yet been reported.

Considering the good redox properties of Ni based compounds, in this work, we developed a NiO nanosheet arrays on TM by a facile hydrothermal method, followed by in-situ growth of Ni-MOF on NiO arrays surface (NiO@Ni-MOF/TM). The NiO@Ni-MOF/TM was directly used as free-standing electrode for electrochemical sensing of luteolin. The NiO@Ni-MOF/TM integrates the remarkable electrical and catalytic properties of NiO/TM and high enrichment ability of Ni-MOF, which effectively improved the electron-transfer kinetics and accumulated more luteolin on the electrode. Under the optimum conditions, the luteolin sensor showed a low LOD of 3 pM, and wide linear ranges of 0.01 nM–1 nM and 1 nM −50 μM. The method was successfully applied to the detection of luteolin contents in Duyiwei capsule sample.

Section snippets

Materials and apparatuses

Luteolin was acquired from XF Nano Co. Ltd. (Nanjing, China). Duyiwei capsules were purchased from Gansu Duyiwei biopharmaceutical Co. Ltd. (China). Ti mesh was provided by Kangwei wire mesh (Hengshui, China). Alcohol (95%), Nickel nitrate hexahydrate (Ni(NO3)2·6H2O), NH4F, urea, 2-methylimidazole (2-MeIM), Na2HPO4 and NaH2PO4 were gotten from Ganyi Technology Co. Ltd. (Jiangxi, China). Luteolin solution was dispersed with alcohol. Phosphate buffer solution (PBS) with pH from 3.0 to 7.0 was

Characterization of structure and morphology

The morphologies of NiO/TM nanosheet arrays and NiO@Ni-MOF/TM nanosheet arrays were observed by scanning electron microscope (SEM). As shown in Fig. 1A, it was found that the surface of TM was uniformly covered by NiO nanosheet arrays. After chemical bath treatment in MIM solution, the granular Ni-MOF was grown on the surface of the NiO nanosheet arrays (Fig. 1B). Meanwhile, we can see that the morphology and structure of the nanosheet arrays were maintained, endowing it with enormous

Conclusion

In this work, 3D hierarchical NiO@MOF nanoarrays were successfully synthesized on TM and developed as a novel electrochemical sensing platform for luteolin determination. The obtained NiO@Ni-MOF/TM possessed large surface area, more active sites, fast electron transport, and good electrolyte penetration, leading to excellent electrocatalytic activity toward the oxidation-reduction of luteolin. As electrochemical sensor, the resulting electrode showed superior sensing performances with linear

CRediT authorship contribution statement

Feng Gao: Conceptualization, Methodology, Writing - original draft, Funding acquisition. Xiaolong Tu: Methodology, Investigation, Validation. Xue Ma: Methodology, Formal analysis, Writing - review & editing. Yu Xie: Methodology, Writing - review & editing. Jin Zou: Writing - review & editing, Investigation, Visualization. Xigen Huang: Investigation, Visualization. Fengli Qu: Supervision, Project administration, Funding acquisition, Writing - review & editing. Yongfang Yu: Investigation,

Declaration of competing interest

The authors declare that there are no conflicts of interest.

Acknowledgements

We are grateful to the National Natural Science Foundation of China (51862014, 31741103, 21665010, 21563014 and 51302117), the outstanding youth fund of Jiangxi Province (20162BCB23027), the Natural Science Foundation of Jiangxi Province (20171BAB203015), Provincial Projects for Postgraduate Innovation in Jiangxi (YC2019–S182) and National College Students' innovation and entrepreneurship training program (201810410013) for their financial support of this work.

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