An "on-off-on" electrochemiluminescence aptasensor based on a self-enhanced luminophore for ochratoxin A detection

Maosheng Sang; Xiaoya Meng; Yuhao Zhang; Zhongyu Li; Quanlong Zhou; Xiangzhu Jing; Xia Sun; Wenping Zhao

doi:10.1007/s00216-023-04864-8

An "on-off-on" electrochemiluminescence aptasensor based on a self-enhanced luminophore for ochratoxin A detection

Anal Bioanal Chem. 2023 Sep;415(23):5833-5844. doi: 10.1007/s00216-023-04864-8. Epub 2023 Jul 21.

Authors

Maosheng Sang^{1

2

3}, Xiaoya Meng^{1

2

3}, Yuhao Zhang^{1

2

3}, Zhongyu Li^{1

2

3}, Quanlong Zhou^{1

2

3}, Xiangzhu Jing^{1

2

3}, Xia Sun^{1

2

3}, Wenping Zhao^{4

5

6}

Affiliations

¹ School of Agricultural Engineering and Food Science, Shandong University of Technology, No. 266 Xincun Xilu, Zibo, 255049, China.
² Shandong Provincial Engineering Research Center of Vegetable Safety and Quality Traceability, No. 266 Xincun Xilu, Zibo, 255049, China.
³ Zibo City Key Laboratory of Agricultural Product Safety Traceability, No. 266 Xincun Xilu, Zibo, 255049, China.
⁴ School of Agricultural Engineering and Food Science, Shandong University of Technology, No. 266 Xincun Xilu, Zibo, 255049, China. zhaowenping@sdut.edu.cn.
⁵ Shandong Provincial Engineering Research Center of Vegetable Safety and Quality Traceability, No. 266 Xincun Xilu, Zibo, 255049, China. zhaowenping@sdut.edu.cn.
⁶ Zibo City Key Laboratory of Agricultural Product Safety Traceability, No. 266 Xincun Xilu, Zibo, 255049, China. zhaowenping@sdut.edu.cn.

PMID: 37477648
DOI: 10.1007/s00216-023-04864-8

Abstract

A highly selective and sensitive "on-off-on" electrochemiluminescence (ECL) aptasensor based on a self-enhanced luminophore was developed for the detection of ochratoxin A (OTA). Specifically, polyethyleneimine functionalized multi-walled carbon nanotubes decorated with gold nanoparticles (AuNPs-PEI-MWCNTs) were used as the electrode matrix to accelerate electron transfer and provide a favorable microenvironment for self-enhanced luminophore loading and ECL signal enhancement. In addition, black phosphorus quantum dots (BPQDs) were used as co-reactants of the ECL reagent tris (2,2'-bipyridyl) ruthenium(II) (Ru(bpy)₃²⁺) in ECL experiments, and the reaction mechanism was investigated. The self-enhanced luminophore Ru@SiO₂-BPQDs was obtained by encapsulating Ru(bpy)₃²⁺ in silica (SiO₂) nanoparticles and then combining it with BPQDs through electrostatic interaction. In conventional ECL systems, the emitter and its co-reactants reacted via the inter-nanoparticle pathway, leading to long distance electron transfer. However, the electron transfer distance in the self-enhanced luminophore was significantly shortened due to the intra-nanoparticle electron transfer pathway because BPQDs and oxidized Ru(bpy)₃²⁺ were bound within one nanoparticle, thereby improving ECL efficiency to achieve the first "switch-on" state. Then, the luminophore was quenched using ferrocenes (Fc) modified on an aptamer to achieve the "switch-off" state. Finally, OTA was specifically identified by the adapter, causing Fc to be released from the sensor interface, restoring the ECL intensity to achieve the second "switch-on" state. Under optimal conditions, the aptasensor exhibited good sensitivity, stability, and reproducibility, with a linear detection range from 0.1 to 320 ng/mL and a detection limit of 0.03 ng/mL. The novel ECL aptasensor provided a common analytical tool for the detection of mycotoxins and other small molecules.

Keywords: Aptasensor; Electrochemiluminescence; Ochratoxin A; Self-enhanced luminophore.

MeSH terms

Aptamers, Nucleotide*
Biosensing Techniques*
Electrochemical Techniques
Gold
Luminescent Measurements
Metal Nanoparticles*
Metallocenes
Nanotubes, Carbon*
Reproducibility of Results
Silicon Dioxide

Substances

ochratoxin A
Gold
Silicon Dioxide
Nanotubes, Carbon
Aptamers, Nucleotide
Metallocenes