Label-free fluorescence aptasensor for ochratoxin A using crystal violet as displacement-type probe

Yang, Cheng; Dong, Shiqi; Abbas, Fathimath; Chu, Xiaolin; Fan, Aiqiao; Rhouati, Amina; Mao, Jin; Liu, Yang

doi:10.1016/j.cjac.2021.07.005

Cited by 3 publications

(9 citation statements)

References 33 publications

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“…Therefore, based on this principle, OTA and K + can be quantitatively monitored in the solution. For an antiparallel G-quadruplex, we designed a new aptamer that truncated five useless bases from the 3′ end of the original OTA aptamer (OTAapt36) to create a new blunt end aptamer (OTAapt31) [ 21 ], which can effectively shorten the distance between fluorophore and quencher, enabling a detection that could not be achieved before. As shown in Figure 1 A, it was observed that the system exhibited a significant fluorescence intensity at 525 nm in the absence of OTA, which was attributed to the binding of SGI to the duplex helix strand.…”

Section: Resultsmentioning

confidence: 99%

“…The standard addition recovery experiment determined the OTA in the red wine sample. The spiked samples were pretreated using the extraction protocol described in our previous study [ 21 ]. The samples after pretreatment were detected according to the method described in Section 2.4 , and the fluorescence intensity was recorded.…”

Section: Resultsmentioning

confidence: 99%

“…The sequence forming the antiparallel G-quadruplex is a new aptamer, which truncated five useless bases from the 3′ end of the original OTA aptamer (OTAapt36) to create a new blunt end aptamer (OTAapt31) [ 21 ]. OTA-A9 to OTA-A12 are the sequences to form a hybrid with an OTA aptamer.…”

Section: Methodsmentioning

confidence: 99%

“…In the spike recovery experiment, 2.0 µL, 4.0 µL, and 8.0 µL of 10 µM OTA standard solution were added to 10 mL of red wine samples to obtain a series of spiked sample solutions. The spiked samples were pretreated using the extraction protocol described in our previous study [ 21 ]. The samples after pretreatment were detected according to the method described in Section 2.4 , and the fluorescence intensity was recorded.…”

Section: Methodsmentioning

confidence: 99%

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Development of Fluorescent Aptasensors Based on G-Quadruplex Quenching Ability for Ochratoxin A and Potassium Ions Detection

Yang

Chu

Zeng³

et al. 2022

Biosensors

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G-quadruplexes have received significant attention in aptasensing due to their structural polymorphisms and unique binding properties. In this work, we exploited the fluorescence-quenching properties of G-quadruplex to develop a simple, fast, and sensitive platform for fluorescence detection of ochratoxin A (OTA) and potassium ions (K+) with a label-free fluorophore and quencher strategy. The quenching ability of G-quadruplex was confirmed during the recognition process after the formation of the G-quadruplex structure and the quenching of the labeled fluorescein fluorophore (FAM). The fluorescence-quenching mechanism was studied by introducing specific ligands of G-quadruplex to enhance the quenching effect, to show that this phenomenon is due to photo-induced electron transfer. The proposed fluorescence sensor based on G-quadruplex quenching showed excellent selectivity with a low detection limit of 0.19 nM and 0.24 µM for OTA and K+, respectively. Moreover, we demonstrated that our detection method enables accurate concentration determination of real samples with the prospect of practical application. Therefore, G-quadruplexes can be excellent candidates as quenchers, and the strategy implemented in the study can be extended to an aptasensor with G-quadruplex.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Development of Fluorescent Aptasensors Based on G-Quadruplex Quenching Ability for Ochratoxin A and Potassium Ions Detection

Yang

Chu

Zeng³

et al. 2022

Biosensors

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“…The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/molecules28124841/s1, Figure S1: Chemistry structural of Ochratoxin A; Table S1: A list of label-free fluorescence aptasensor for OTA detection. References [31][32][33][34][35] are cited in the supplementary materials.…”

Section: Supplementary Materialsmentioning

confidence: 99%

Molecular Docking Insight into the Label-Free Fluorescence Aptasensor for Ochratoxin A Detection

Wang

et al. 2023

Molecules

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Ochratoxin A (OTA) is the most common mycotoxin and can be found in wheat, corn and other grain products. As OTA pollution in these grain products is gaining prominence as a global issue, the demand to develop OTA detection technology has attracted increasing attention. Recently, a variety of label-free fluorescence biosensors based on aptamer have been established. However, the binding mechanisms of some aptasensors are still unclear. Herein, a label-free fluorescent aptasensor employing Thioflavin T (ThT) as donor for OTA detection was constructed based on the G-quadruplex aptamer of the OTA aptamer itself. The key binding region of aptamer was revealed by using molecular docking technology. In the absence of the OTA target, ThT fluorescent dye binds with the OTA aptamer to form an aptamer/ThT complex, and results in the fluorescence intensity being obviously enhanced. In the presence of OTA, the OTA aptamer binds to OTA because of its high affinity and specificity to form an aptamer/OTA complex, and the ThT fluorescent dye is released from the OTA aptamer into the solution. Therefore, the fluorescence intensity is significantly decreased. Molecular docking results revealed that OTA is binding to the pocket-like structure and surrounded by the A29-T3 base pair and C4, T30, G6 and G7 of the aptamer. Meanwhile, this aptasensor shows good selectivity, sensitivity and an excellent recovery rate of the wheat flour spiked experiment.

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Design of a Quencher-Free Fluorescent Aptasensor for Ochratoxin A Detection in Red Wine Based on the Guanine-Quenching Ability

et al. 2022

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This study describes a quencher-free fluorescent aptasensor for ochratoxin A (OTA) detection using the specific quenching ability of guanine for fluorescein (FAM) molecules based on photo-induced electron transfer (PIET). In this strategy, OTA is detected by monitoring the fluorescence change induced by the conformational change of the aptamer after target binding. A new shorter OTA aptamer compromising three guanine bases at the 5′ end was used in this study. This new aptamer, named G3-OTAapt1-FAM (F1), was labeled with FAM on the 3′ end as a fluorophore. In order to increase the binding affinity of the aptamer and OTA, G3-OTAapt2-FAM (F2) was designed; this added a pair of complementary bases at the end compared with F1. To prevent the strong self-quenching of F2, a complementary chain, A13, was added. Although the F1 aptasensor was simpler to implement, the sensitivity of the F2 aptasensor with A13 was better than that of F1. The proposed F1 and F2 sensors can detect OTA with a concentration as low as 0.69 nmol/L and 0.36 nmol/L, respectively.

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Label-free fluorescence aptasensor for ochratoxin A using crystal violet as displacement-type probe

Cited by 3 publications

References 33 publications

Development of Fluorescent Aptasensors Based on G-Quadruplex Quenching Ability for Ochratoxin A and Potassium Ions Detection

Development of Fluorescent Aptasensors Based on G-Quadruplex Quenching Ability for Ochratoxin A and Potassium Ions Detection

Molecular Docking Insight into the Label-Free Fluorescence Aptasensor for Ochratoxin A Detection

Design of a Quencher-Free Fluorescent Aptasensor for Ochratoxin A Detection in Red Wine Based on the Guanine-Quenching Ability

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