TALANTA
·
2019
·
IF 4.916
Tian Wu,Xiang Li,Yuanqi Fu,Xuelian Ding,Zhongjian Li,Guifen Zhu,Jing Fan
Developing the high selectivity and sensitivity strategy for nucleic acid detection is crucial for early diagnosis and therapy of diseases. In this work, a novel low back-ground fluorescent sensor platform for the detection of nucleic acid has been developed based on δ-FeOOH nanosheets integrating with exonuclease III-assisted target-recycling signal amplification. Because of the strong binding ability between the single-strand DNA (ssDNA) and the δ-FeOOH nanosheets, the dye-labeled ssDNA probe would be quenched by δ-FeOOH nanosheets through fluorescence resonance energy transfer (FRET). By using magnetic separate properties of δ-FeOOH, the background signal was separated from the sensor system, and the low background sensor system was obtained. After adding the target DNA, a double-strand DNA complex (dsDNA) would be formed between the target DNA and dye-labeled ssDNA probe. Then, the dye-labeled ssDNA probe in the dsDNA complex would be stepwise hydrolyzed into short fragments from 3′-terminus by Exonuclease III, and the fluorescence signal was recovered due to the weak bind affinity between the short fragments and δ-FeOOH nanosheets. By using the fluorescence quenching ability of δ-FeOOH nanosheets and enzyme-assisted target-recycling signal amplification, this strategy could show an excellent selectivity toward hepatitis C virus DNA with a low detection limit of 10 pM. By simply changing the dye-labeled ssDNA probe sequence, this sensing platform can be developed as a universal approach for the simple, sensitive, and selective detection of different target DNA.
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高影响因子
TALANTA
·
2023
·
IF 6.1
Lidong Pang,Ling'e Wang,Yaqi Liang,Zhenghui Wang,Wei Zhang,Qianyu Zhao,Xinyan Yang,Yujun Jiang
Escherichia coli O157: H7 ( E. coli O157: H7) is one of the most common foodborne pathogens and is widespread in food and the environment. Thus, it is significant for rapidly detecting E. coli O157: H7. In this study, a colorimetric aptasensor based on aptamer-functionalized magnetic beads, exonuclease III (Exo III), and G-triplex/hemin was proposed for the detection of E. coli O157: H7. The functional hairpin HP was designed in the system, which includes two parts of a stem containing the G-triplex sequence and a tail complementary to cDNA. E. coli O157: H7 competed to bind the aptamer (Apt) in the Apt-cDNA complex to obtain cDNA. The cDNA then bound to the tail of HP to trigger Exo III digestion and release the single-stranded DNA containing the G-triplex sequence. G-triplex/hemin DNAzyme could catalyze TMB to produce visible color changes and detectable absorbance signals in the presence of H 2 O 2 . Based on the optimal conditions, E. coli O157: H7 could be detected down to 1.3 × 10 3 CFU/mL, with a wide linear range from 1.3 × 10 3 to 1.3 × 10 7 CFU/mL. This method had a distinguished ability to non-target bacteria, which showed good specificity. In addition, the system was successfully applied to detect E. coli O157: H7 in milk samples.
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高影响因子
TALANTA
·
2024
·
IF 5.6
Lei-Xin Jin,Qi-Meng Wang,Shu-Jiao Zhu,Cai-Lian Zhu,Jian-Jun Sun,Shao-Hua Wu
The flap endonuclease 1 (FEN1) plays a key role in DNA replication and repair, its aberrant expression is associated with tumor development, so it has been recognized as a promising biomarker for a variety of cancers. Here, a novel “turn on” mode gold nanocube-enhanced surface-enhanced Raman scattering (SERS) biosensor was constructed by combining a heated Au electrode (HAuE), exonuclease III (Exo III)-assisted cycle amplification, and gold nanocube (AuNC)-based SERS enhancement to achieve highly sensitive detection of FEN1 activity. The SERS tag was prepared using the Raman reporter modified on the AuNC surface, and the high electromagnetic field provided by the sharp geometric feature of AuNC greatly enhanced the SERS signal. At the same time, HAuE was used to increase the electrode surface temperature and enhance the FEN1 activity, leading to more trigger DNA being cleaved, which was used to initiate the Exo III-assisted cycle amplification. Taking all these advantages, the proposed method possessed high sensitivity and good selectivity, with a low limit of detection (LOD) of 3.19 × 10 −7 U μL −1 . In addition, this method was successfully applied to detect FEN1 activity in real cellular extracts.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Xiaolun Peng,Jiaxin Zheng,Ting Bao,Wei Wen,Xiuhua Zhang,Shengfu Wang
A novel dual-amplified electrochemical biosensor based on Exonuclease III (Exo III) and Cu(II)-dependent DNAzymes (Cu 2+ -DNAzymes) was developed for ultrasensitive electrochemical evaluation of pyrophosphatase (PPase) activity with the help of one-step synthesis of BSA-directed gold nanoclusters-manganese dioxide (AuNCs-MnO 2 ) nanoflakes with peroxidase-like characteristics as a catalytic platform. For biosensor preparation, under the catalytic hydrolysis of the PPase, copper ion (Cu 2+ ) was released from the Cu 2+ -coordinated pyrophosphate ions (Cu 2+ –PPi) complex which was formed by the coordination reaction of copper ion (Cu 2+ ) and pyrophosphate ions (PPi). The released Cu 2+ , acting as an indispensable cofactor, could activate Cu 2+ -DNAzymes to turn on the amplification process and then generated the single-stranded product (S1) that hybridized to the hairpin-type capture probe (HP1). Subsequently, the addition of Exonuclease III (Exo III) enabled the reuse of S1 and produced the final cleavage fragment, which closely linked the functionalized AuNCs-MnO 2 nanoflakes to the electrode surface. The superior peroxidase-like characteristics of nanoflakes provided stable catalytic signal output and realized electrochemical monitoring of PPase activity with a detection limit of 0.0058 mU/mL. Importantly, the biosensor also had a good performance in inhibitors screening of target PPase. The use of AuNCs-MnO 2 nanoflakes instead of natural enzymes combined with DNAzymes amplification strategy offered more possibilities for the detection of various biomolecules.
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ANALYTICAL CHEMISTRY
·
2016
·
IF 5.886
Wang Ren,Ying Zhang,Hong Guo Chen,Zhong Feng Gao,Nian Bing Li,Hong Qun Luo
A novel signal-on and label-free resonance Rayleigh scattering (RRS) aptasensor was constructed for detection of Hg2+ based on Hg2+-triggered Exonuclease III-assisted target recycling and growth of G-quadruplex nanowires (G-wires) for signal amplification. The hairpin DNA (H-DNA) was wisely designed with thymine-rich recognition termini and a G-quadruplex sequence in the loop and employed as a signal probe for specially recognizing trace Hg2+ by a stable T–Hg2+–T structure, which automatically triggered Exonuclease III (Exo-III) digestion to recycle Hg2+ and liberate the G-quadruplex sequence. The free G-quadruplex sequences were self-assembled into guanine nanowire (G-wire) superstructure in the presence of Mg2+ and demonstrated by gel electrophoresis. The RRS intensity was dramatically amplified by the resultant G-wires, and the maximum RRS signal at 370 nm was linear with the logarithm of Hg2+ concentration in the range of 50.0 pM to 500.0 nM (R = 0.9957). Selectivity experiments revealed that the as-prepared RRS sensor was specific for Hg2+, even coexisting with high concentrations of other metal ions. This optical aptasensor was successfully applied to identify Hg2+ in laboratory tap water and river water samples. With excellent sensitivity and selectivity, the proposed RRS aptasensor was potentially suitable for not only routine detection of Hg2+ in environmental monitoring but also various target detection just by changing the recognition sequence of the H-DNA probe.
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高影响因子
ANALYST
·
2022
·Vol. 147
·期 11
·2412-2424
·
IF 5.227
Dongyou Zhang,Yali Wang,Xiaoyu Jin,Qi Xiao,Shan Huang
A label-free and ultrasensitive electrochemical biosensor for oral cancer overexpressed 1 (ORAOV1) gene was constructed via exonuclease III-assisted target recycling and dual enzyme-assisted signal amplification strategies. Capture DNA with a sulfhydryl group at its 3′ terminus was modified onto the surface of a bare gold electrode via an Au–S bond. Assisted DNA hybridized with basal DNA to form hybrid DNA in advance, and ORAOV1 gene hybridized continuously with such a hybrid DNA from the other terminus to construct intact double-stranded DNA. Exonuclease III digested basal DNA in such intact double-stranded DNA specifically, and both ORAOV1 gene and assisted DNA were released into solution. ORAOV1 gene induced another intact double-stranded DNA digestion for target recycling, while assisted DNA hybridized with the capture DNA to form double-stranded DNA on the modified electrode surface. Unhybridized capture DNA on the modified electrode surface was hydrolyzed by RecJf exonuclease to reduce the background electrochemical signal. The 3′ terminus of double-stranded DNA on the modified electrode surface was prolongated to be guanine-rich oligonucleotides under the catalysis of terminal deoxynucleotidyl transferase. In the presence of K+ ions, hemin adsorbed onto guanine-rich oligonucleotides to construct a G-quadruplex/hemin complex with a large steric hindrance effect to efficiently avoid the charge transfer of the [Fe(CN)6]3−/4− probe toward the electrode surface. The electrochemical impedance value was increased significantly after the addition of ORAOV1 gene via exonuclease III-assisted target recycling and dual enzyme-assisted signal amplification strategies. The electrochemical impedance value was linearly related to the logarithmic concentration of ORAOV1 gene in the range from 0.05 fM to 20 pM, and the detection limit of ORAOV1 gene was low to 0.019 fM. This biosensor was used to detect ORAOV1 gene in complicated human saliva samples with satisfactory results.
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高影响因子
FOOD CONTROL
·
2022
·
IF 6.652
Chengyuan Wu,Xiangchuan Wu,Fan Hou,Lina Wu,Guangxia Liu
An ultrasensitive electrochemical aptasensor was established based on metalloporphyrin metal organic frameworks ( [email protected] ) with peroxidase-like activity and exonuclease III-assisted recycling magnification for the detection of ochratoxin A (OTA). [email protected] showed well peroxidase-like activities due to Fe-tetrakis (4-carboxyphenyl) porphyrin (Fe-TCPP) as a heme-like ligand and in situ supported with palladium nanoparticle, which could be used for the label of ssDNA instead of nature enzyme. The designed exonuclease III-assisted recycling magnification further improve the sensitivity for the detection. Based on this, the proposed aptasensor showed a well linear relationship within the scope of 1 × 10 −5 ng mL −1 to 10 ng mL −1 and a low detection limit of 6.79 fg mL −1 . Additionally, the application in the real spiked oil samples confirmed the dependability and veracity of the aptasensor. Hence, the designed aptasensor has comprehensive application prospects for the detection of OTA in food .
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FOOD CHEMISTRY
·
2022
·
IF 9.231
Xiaodong Cao,Minli Liu,Jie Lu,Hongge Lv,Jinzhe Han,Shudong He,Yongkang Ye,Xiangyang Chen,Zhaojun Wei,Haisong Zheng
This work presented an electrochemical biosensor for the detection of virulence outer membrane protein A ( ompA ) gene of Cronobacter sakazakii ( C. sakazakii ), which was based on the mimic peroxidase activity of boron doped quantum dots-Au nanoparticles (BQDs-AuNPs) and a signal amplification strategy of exonuclease III (Exo III)-assisted target-recycling (EATR). The electrochemical signal was come from the electrochemical reduction of H 2 O 2 by BQDs-AuNPs nanozyme. Due to the enhanced peroxidase-mimic electrocatalytic efficiency of BQDs-AuNPs and the EATR strategy, the biosensor showed a broad linear range (1.0 × 10 -15 – 1.0 × 10 -8 mol L -1 ) and a low limit of detection (LOD, 4.0 × 10 -17 mol L -1 ). The constructed biosensor could also be applied in direct detection of extracted DNA from C. sakazakii . A good linear relationship (7.8 – 7.8 × 10 6 CFU mL −1 ) between the logarithm concentration of C. sakazakii and electrochemical signal was obtained with a LOD of 2.6 CFU mL −1 . The biosensor was applied in the detection of impA gene segments in contaminated infant formula with recoveries ranged in 83.4 – 108.2%.
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MICROCHEMICAL JOURNAL
·
2026
·
IF 5.2
Beili Wang,Wei Gao,Liang Yang
An Exo-III-triggered target-reconstructed DNAzyme walker enables ultrasensitive multiplex miRNA detection. • Cascade amplification integrates Exo-III recycling, polymerase/endonuclease cycling, and DNAzyme walking. • Orthogonal Pt, Ir, Rh tags allow simultaneous ICP-MS quantification of three miRNAs without spectral cross-talk. • Detection limits reach 0.15 fM (miR-21), 0.32 fM (miR-1246), and 0.26 fM (miR-20a) with excellent linearity. • The method discriminates single-base mismatches and performs well in diluted human serum (92–108% recovery). Cervical cancer remains a leading cause of cancer-related mortality among women, and the prognosis of patients after radiotherapy varies considerably due to differences in tumor radiosensitivity and treatment response. Reliable biomarkers for post-radiotherapy prognosis are therefore critically needed. MicroRNAs (miRNAs) have emerged as promising non-invasive indicators, yet accurate detection is hindered by their low abundance and the lack of multiplexing capability in conventional methods. Herein, we report a highly sensitive and specific platform for simultaneous detection of three cervical cancer radiotherapy-associated miRNAs (miR-21, miR-1246, and miR-20a) by integrating an Exo-III-triggered target-reconstructed DNAzyme walker with inductively coupled plasma mass spectrometry (ICP-MS). The strategy employs a structurally locked DNA walker that is sequentially activated through Exo-III-mediated target recycling and DNA polymerase/endonuclease-assisted cyclic amplification, ultimately unleashing a DNAzyme walker to cleave element-labeled substrates. Using orthogonal platinum group element tags (Pt, Ir, Rh), the released tags are quantified by ICP-MS without spectral cross-talk. The method achieves detection limits as low as 0.15 fM, 0.32 fM, and 0.26 fM for miR-21, miR-1246, and miR-20a, respectively, with excellent single-nucleotide discrimination and negligible cross-reactivity. Successful spike-recovery experiments in diluted human serum validate its practical feasibility. This cascade amplification strategy offers a robust, multiplex, and ultrasensitive tool for non-invasive liquid biopsy-based prognostic assessment of post-radiotherapy cervical cancer, and can be readily adapted for other disease-related miRNA panels. Download: Download high-res image (121KB) Download: Download full-size image
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TALANTA
·
2021
·
IF 6.057
Cai-Xia Shi,Yan-Zi Li,Qing Liu,Zeng-Ping Chen,Sha-Sha Li,Ru-Qin Yu
Biosensors based on various spectroscopic techniques discriminate the target microRNA (miRNA) from non-target ones with single nucleotide polymorphisms (SNPs) according to the differences in signal intensities which can be caused by other factors besides SNPs. As a result, they are liable to produce false positive results. Herein, we report an attempt to develop a false-positive resistance, sensitive and reliable mass spectrometric platform for miRNA detection. In the proposed platform, the qualitative and quantitative information of the target miRNA was obtained through analyzing mass spectral responses of the multiply charged ions of the residual fragments of the probe DNA produced during exonuclease III assisted signal amplification reaction using an advanced data analysis method. The proposed platform could achieve sensitive and accurate quantitative results for the target miRNA (e.g., miRNA-141) in complex medium with a detection limit of about 1 pM, and unambiguously identify non-target miRNAs with SNPs based on the length distribution patterns of residual fragments of probe DNA. The findings obtained in this study might open an avenue for the design of new miRNA detection methods based on mass spectrometry in combination with various nuclease assisted signal amplification strategies.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2022
·
IF 7.129
Yi Ning,Xiaoqi Wang,Shiwu Liu,Ling Li,Fangguo Lu
Herein, a graphene oxide (GO)-based fluorescence aptasensor was developed for the sensitive and selective detection of chloramphenicol (CAP), based on exonuclease III (Exo III)-assisted target recycling and Nb.BbvCI-driven DNA walker cascade amplification. Interactions between CAP, hairpin1(HP1), hairpin2 (HP2), and 3′-amino modified hairpin3 (HP3) labeled with carboxyfluorescein (FAM) and covalently coupled to GO enabled efficient CAP detection. CAP was quantitatively assayed by measuring fluorescence at excitation/emission wavelengths of 480/514 nm, resulting from the accumulation of released FAM. A good linear range of 1 fM to 1 nM and a limit of detection (LOD) of 0.875 fM (signal-to-noise ( S/N) = 3) were achieved. This aptasensor can distinguish the CAP from interference antibiotics with good specificity and selectivity, even if the concentration of the interfering substance is ten-fold higher than the target concentration. Moreover, the developed fluorescence aptasensor was successfully applied for the detection of CAP in spiked milk and honey samples. Thus, this method is potentially applicable for assaying CAP in foods and provides a promising strategy for the development of fluorescence aptasensors for environmental sample analysis.
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高影响因子
MICROCHIMICA ACTA
·
2015
·Vol. 182
·期 15
·2607-2613
·
IF 3.741
Yang Zhiqing,Xie Liyan,Yin Huanshun,Zhou Yunlei,Ai Shiyun
We describe an electrochemical bioassay for the detection of the activity of methyltransferase (MTase), and for screening this enzyme’s inhibitors. The assay is based on the conjugation of a hemin to a G-quadruplex that enables enzymatic signal amplification with the aid of exonuclease III (ExoIII). In the first step, double-stranded DNA containing the quadruplex-forming oligomer is assembled on the surface of a gold electrode and then methylated by DNA adenine methyltransferase (DAM). After cleaved by endonuclease DpnI, the methylated DNA is digested by ExoIII and the quadruplex-forming oligomers are liberated. This leads to the formation of a hemin/G-quadruplex (in presence of hemin and of potassium ions). The hemin/G-quadruplex catalyzes the oxidization of hydroquinone by H 2 O 2 and the benzoquinone was formed to generate electrochemical signal. Finally, the gold electrode modified with reduced graphene oxide was used as working electrode for performing differential pulse voltammetry. The method has a detection limit of 0.31 unit · mL −1 . A study on the inhibition of MTase showed it was inhibited by epicatechin with an IC50 value of 157 μM.
We describe an electrochemical bioassay for the detection of the activity of methyltransferase and for screening for its inhibitors. Due to the conjugation of a hemin to a G-quadruplex, strong enzymatic signal amplification is enabled with the aid of exonuclease III.
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