ANALYST
·
2016
·Vol. 141
·期 5
·1830-1836
·
IF 4.033
Xiuzhong Wang,Shanshan Dong,Ting Hou,Lei Liu,Xiaojuan Liu,Feng Li
A novel enzyme inhibition-based homogeneous electrochemical biosensing strategy was designed for an organophosphorus pesticide assay based on exploiting the resistance of a mercury ion-mediated helper probe (HP) toward nuclease-catalyzed digestion and the remarkable diffusivity difference between HPs and the mononucleotides toward a negatively charged indium tin oxide (ITO) electrode. In particular, the mercury ion-mediated T–Hg2+–T base pairs facilitate the HP labeled with methylene blue (MB) to fold into a hairpin structure, preventing its digestion by exonuclease I, and thus resulting in a low electrochemical response because of the large electrostatic repulsion between the negatively charged ITO electrode and the HPs. The competitive binding by a thiol group (–SH), produced in the hydrolysis reaction of acetylthiocholine (ACh) chloride with acetylcholinesterase (AChE), removes mercury ions from the base pairs, causing a nuclease-catalyzed digestion, and the subsequent electrochemical response increase due to the weak electrostatic repulsion between the product-mononucleotides and the ITO electrode. Mercury ion-mediated HPs were first designed for pesticide detection and diazinon was chosen as the model target. Under the optimal experimental conditions, the approach exhibited high sensitivity for diazinon detection with a detection limit of 0.25 μg L−1. The satisfactory results in the determination of diazinon in real samples demonstrate that the method possesses great potential for detecting organophosphorus pesticides. This new approach is expected to promote the exploitation of mercury-mediated base pair-based homogenous electrochemical biosensors in biochemical studies and in the food safety field.
研究领域:
生物化学
·
食品安全
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PubMed
高影响因子
Analytical Methods
·
2024
·Vol. 16
·期 11
·1570-1578
·
IF 2.7
Meijuan Du,Xin Cheng,Qian Chen,Xueqin Xu
In this paper, a novel and sensitive electrochemical aptasensor for sulfadimethoxine (SDM) detection has been designed based on the triple helix structure/exonuclease I (Exo I)-assisted double signal amplification strategy. The aptamer probe (Apt) hybridizes with the signal transduction probe (STP) on the electrode to form a rigid double-stranded DNA (dsDNA) structure, so that the STP remains upright and methylene blue (MB) on the STP is far away from the electrode surface, resulting in a delicate current signal. In the presence of SDM, the SDM and Apt combine into a complex, leading to the transfer of the Apt and the exposure of the STP. Meanwhile, the added Exo I can digest the Apt to realize the cyclic amplification of SDM. After the addition of the signal probe (SP), a triple helix structure between the SP and STP is formed under acidic conditions, and MB on the STP and SP collide with the electrode surface to generate a strong electrochemical signal. The proposed aptasensor combines the features of the triple helix structure and Exo I to achieve double signal amplification for the sensitive detection of SDM with a wide linear range of 0.05–1000 ng mL−1 and a low detection limit of 0.02 ng mL−1. Furthermore, it has been successfully used to detect SDM in milk and lake water samples.
研究领域:
分析化学
·
生物传感技术
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PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2019
·Vol. 411
·期 11
·2405-2414
·
IF 3.286
Wang Chengke,Tan Rong,Li Jiangyu,Zhang Zexiang
In this paper, a fluorescent method was developed for ochratoxin A (OTA) detection that uses iron-doped porous carbon (MPC) and aptamer-functionalized nitrogen-doped graphene quantum dots (NGQDs-Apt) as probes. In this method, the adsorbance of the NGQDs-Apt on the MPC due to a π–π interaction between the aptamer and the MPC results in the quenching of the fluorescence of the NGQDs-Apt. However, since OTA interacts strongly with the aptamer, the presence of OTA leads to the detachment of the NGQDs-Apt from the MPC, resulting in the resumption of fluorescence from the NGQDs-Apt. When exonuclease I (Exo I) is also added to the solution, this exonuclease specifically digests the aptamer, leading to the release of the OTA back into the solution. This free OTA then interacts with another MPC–NGQDs-Apt system, inducing the release of more NGQDs into the solution, which enhances the fluorescent intensity compared to that of the system with no Exo I. Utilizing this behavior of OTA in the presence of NGQDs-Apt, it was possible to detect concentrations of OTA ranging from 10 to 5000 nM, with a limit of detection of 2.28 nM. Our method was tested by applying it to the detection of OTA in wheat and corn samples. This method has four advantages: (1) the magnetic porous carbon is easy to prepare, its porosity enhances its loading capacity for NGQDs, it highly efficiently quenches the fluorescence of the NGQDs, and its magnetic properties facilitate the separation of the MPC from other species in solution; (2) applying double magnetic separation decreases the background signal; (3) Exo I digests the free aptamer effectively, which allows the resulting free OTA to induce the release of more NGQDs-Apt, ultimately enhancing the fluorescent signal; and (4) the proposed method presented high sensitivity and a wide linear detection range. This method may prove helpful in food safety analysis and new biosensor development (achieved by using different aptamer sequences to that used in the present work).
Exonuclease I (Exo I)-assisted fluorescent method for ochratoxin A (OTA) detection using magnetic porous carbon (MPC), nitrogen-doped graphene quantum dots (NGQDs), and double magnetic separation
研究领域:
食品安全
·
生物传感
·
分析化学
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DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2025
·Vol. 193
·期 1
·15
·
IF 5.3
Zhang Yan,Yan Yuting,Huang Yue
An innovative electrochemical biosensor is proposed for the sensitive detection of ofloxacin (OFL) by integrating exonuclease I (Exo I)–assisted recognition-transduction strategy into the MXene/AuNP-enhanced electrochemical platform. Through ingenious design, the presence of OFL triggers the competitive displacement reaction and enables Exo I to hydrolyze the released single-stranded DNA probe containing the sequence of Pb 2+ -DNAzyme, protecting the signal probes on the electrode surface from DNAzyme cleavage, which eventually brings about a remarkable electrochemical signal positively related to the concentration of OFL. MXene/AuNPs with excellent conductivity, large specific surface area, and good chemical stability are employed as the electrode substrate to efficiently accelerate charge transfer and increase the loading capacity for signal probes, leading to the enhancement of signal output and endowing the biosensor with high sensitivity, rapid response, and fine robustness. Taking advantage of OFL recognition–initiated Exo I hydrolysis to DNAzyme, the electrochemical platform with “signal-off/on” mode can detect OFL with good specificity and reduced background interference. Benefiting from the synergistic effect of the involved sensing elements, the developed electrochemical biosensor achieves a low detection limit of 0.47 pg mL −1 with a broad linear range and exhibits satisfactory detection performance in real food samples, indicating potential practical applicability in food safety monitoring. Graphical
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Methods and Applications in Fluorescence
·
2019
·Vol. 8
·期 1
·015003
·
IF 2.94
Lei Lv,Chengbi Cui,Wancui Xie,Wenyi Sun,Shuang Ji,Jing Tian,Zhijun Guo
A novel label-free fluorescence aptasensor used for the detection of ochratoxin A (OTA) is presented in this study. When aggregated on the surface of DNA aptamer, aggregation-induced emission (AIE) fluorescence probe presents turn-on fluorescence property. The method proposed in this article was based on an AIE probe, 4, 4-(1E,1E)-2, 2-(anthracene-9, 10-diyl) bis (ethene-2, 1-diyl) bis (N, N, N-trimethylbenzenaminium iodide) (DSAI). With OTA present, the aptamer will combine with OTA and the conformation of the aptamer will switch to an antiparallel G-quadruplex from the initial random coil, which obstructs its digestion by Exo I. After the solution is added with DSAI, DSAI will aggregate on the surface of the aptamer/OTA complex and produces a strong emission. In the range of 5 to 500 ng · ml−1 OTA concentrations, the fluorescence increases with a linear logarithm relationship. The detection limit is 1.9 ng · ml−1. This method was used to detect OTA in spiked real samples, with recoveries and RSDs in the range of 92.2% to 106.3%, and 2.7% to 5.2%, respectively.
研究领域:
食品科学
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分析化学
·
毒理学
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高影响因子
MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Jian Yang,Jiahua Li,Xuan Yi,Shiyuan Feng,Wei Kang,Gang Ren,Jianli Liu,Chen Mai,Jinfeng Miao,Yuanyuan Xu
Energy levels in organisms are closely linked to metabolic diseases, with ATP—the universal energy currency—playing a central role in this relationship. This paper presents a novel electrochemical biosensor for ATP, integrating homogeneous bio-recognition reactions with terminal deoxynucleotidyl transferase (TdT)-mediated polymerization to enable precise ATP detection in metabolic research. Initially, a DNA oligonucleotide composed of a camouflaged aptamer and exposed hairpin DNA was designed to react homogeneously with ATP in the presence of exonuclease I (Exo I). This reaction generates blunt-ended hairpin DNA, which can activate the assembly of an ordered DNA-rich nanostructure layer on the gold electrode. Subsequently, the DNA strand is elongated through TdT-induced polymerization in the presence of deoxynucleotide triphosphates (dNTPs). A significant amount of Ru(NH 3 ) 6 3+ can be adsorbed onto the negatively charged DNA phosphate backbone via strong electrostatic interactions, effectively amplifying the detection signal and enhancing the sensor's performance. Under optimal conditions, the system exhibits excellent linearity over the target concentration range of 10 −2 to 10 3 nM, with a detection limit as low as 8.37 pM, enabling the detection of trace amounts of ATP. The biosensor demonstrates high stability and reliability, with recovery rates ranging from 97.8 % to 110 %. This method serves as a diagnostic tool to assess organismal metabolic status by monitoring ATP levels, enabling the tracking of metabolic disease progression. By integrating molecular monitoring with clinical diagnosis, it offers a potential approach for the preventing and intervention of metabolic diseases.
研究领域:
生物电化学
·
生物传感器
·
分子诊断
·
核酸扩增
·
代谢研究
·
临床诊断
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高影响因子
Journal of Materials Chemistry B
·
2018
·Vol. 6
·期 45
·7503-7510
·
IF 4.776
Huan Liu,Luping Feng,Yuanyuan Cai,Yue Hua,Min Liu,Mengyuan Yin,Shuai Li,Xiaoxia Lv,Jiangwei Wen,Hua Wang
An ultrasensitive and high-throughput visualized colorimetric method has been initially developed with a wettable microwells array for probing guanine base-containing anthrax DNAs in blood based on silver deposition amplified by the synergic TiO2 photocatalysis and guanine photoreduction under visible light. Hydrophilic microwells were first created on the hydrophobic slides to yield the wettable microwells array, on which photocatalytic titanium dioxide (TiO2) nanoparticles were deposited with dopamine (DA) to yield TiO2@DA for anchoring single strand DNA (ssDNA) capture probes without guanine bases. After the hybridization of the targeted anthrax DNAs, exonuclease I (Exo I) was introduced into the microwells to selectively digest the unhybridized ssDNA probes. The silver deposition was further conducted by the synergic photocatalysis of TiO2@DA and photoreduction of guanine bases of anthrax DNAs, thus achieving the amplified silver signals for the visualized colorimetric assays. Moreover, benefitting from the wettability feature of the hydrophilic–hydrophobic interfaces of the microwells array so fabricated, DNA analytes could be accumulated from the sample droplets through the condensing enrichment process to realize the ultrasensitive detection, in addition to circumventing any crossover contaminants between the sample droplets. The developed visualized colorimetric method with the microwells array was subsequently applied for probing anthrax DNAs in blood with levels down to 1.0 fM. DNAs with single-base and double-base mutations could also be identified accurately. Importantly, such a biosensing design route of a wettable microwells array, in combination with the photocatalytic silver deposition and specific Exo I-catalytic probe digestion, may promise extensive applications for the high-throughput, ultrasensitive, and selective detection of guanine-containing DNA targets with ultra-trace levels in complicated samples like blood.
研究领域:
生物化学
·
分析化学
·
纳米技术
·
分子生物学
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PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Guoli Xu,Jingzhou Hou,Yanan Zhao,Jing Bao,Mei Yang,Huanbao Fa,Yixia Yang,Li Li,Danqun Huo,Changjun Hou
A highly sensitive dual-signal aptamer sensor based on polydopamine-gold nanoparticles (PDA-AuNPs) and exonuclease I (Exo I) was developed for detection of malathion. Compared with traditional sensing elements, aptamer has many advantages, such as high affinity, superior specificity, strong stability and easy modification. The electrodeposition synthesis of PDA-AuNPs gave excellent biocompatibility and electrical conductivity on the sensor. With the addition of malathion, the specific interaction between malathion and its aptamer forced the aptamer to detach from the electrode surface and induced the capture probe to form a hairpin structure on the electrode surface. Exo I was added to motivate the autocatalytic target cycling which remarkably increased the current change of electrochemical signal over 2 times. Therefore, the promising strategy gave rise to an optional dual-signal current readout in both the signal-on of Fc and the signal-off of Tn. In this work, the prepared biosensor exhibited high sensitivity to malathion via the combination of dual-signal design and autocatalytic target cycling amplification. Under the optimized conditions, the proposed sensor showed a wide linear range from 0.5 to 600 ng/L malathion. It also exhibited excellent specificity, acceptable repeatability and good stability. The application of real samples obtained satisfactory recovery results, demonstrating a promising potential in food safety analysis.
研究领域:
分析化学
·
纳米技术
·
生物传感器
·
环境科学
·
食品安全
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高影响因子
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