ANALYST
·
2021
·Vol. 146
·期 8
·2664-2669
·
IF 4.616
Liling Lu,Xiao Han,Jingwen Lin,Yingxin Zhang,Minghao Qiu,Ying Chen,Meijin Li,Dianping Tang
Herein a rapid and sensitive fluorometric bioanalysis platform for mercury(II) (Hg2+) detection was innovatively developed using ultrathin two-dimensional MXenes (Ti3C2) as fluorescence quencher and Hg2+-induced exonuclease III (Exo III)-assisted target recycling strategy for efficient signal amplification. Initially, fluorophore-labeled single-stranded DNA (FAM-labeled probe) can be easily adsorbed onto the surface of ultrathin Ti3C2 nanosheets by hydrogen bonding and metal chelating interaction, and the fluorescence signal emitted by the FAM-labeled probe is quenched strongly owing to the fluorescence resonance energy transfer between the FAM and ultrathin Ti3C2 nanosheets. Upon sensing the target Hg2+, the protruding DNA fragment at the 3′ end of hairpin will hybridize with primer (hairpin-Hg2+-primer), and then further digested by Exo III to produce a probe (nicker). The released target Hg2+ and primer continue to participate in the next recycling, resulting in more hairpin probes becoming nickers. The combination of a large number of nickers and FAM-probe resulted in a significant increase in the fluorescence signal of the system, which was attributed to the fact that the double helix DNA was more rigid and separated from the surface of the ultrathin Ti3C2 nanosheets. The obvious fluorescence signal change of the Ti3C2-based Exo III-assisted target recycling can be accurately monitored by fluorescence spectrometry, which is also proportional to the concentration of Hg2+. Under optimum operating conditions, the peak intensity (520 nm wavelength) of fluorescence increased with increasing Hg2+ within a wide dynamic working range from 0.05 nM to 50 nM (R2 = 0.9913) with a limit of detection down to 42.5 pM. The proposed strategy uses ultrathin MXenes as a platform for binding nucleic acids, which contributes to its potential in nucleic acid hybridization-based biosensing and/or nucleic acid signal amplification bio-applications.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Kai Wen,Xingdong Yang,Cuiling Zhang,Huiying Wei,Guizheng Zou,Ye Zhu
Diffusion-mediated homogeneous electrochemical assay has attracted substantial attention owing to its simplicity, rapid response, and high recognition efficiency, however, lack of inherent connection between signal reporter and electrode surface restricts the improvement of detection sensitivity and further limits its potential applications. Herein, a facile electrochemical strategy is proposed through integrating the advantages of traditional heterogeneous assay and homogenous assay. In this strategy, a small amount of target DNA can trigger the release of assist DNA from the electrode surface. Then, the assist DNA can induce the homogeneous amplification reaction, which in turn promotes the amplification on the electrode surface by generating numerous target DNA analogues, thereby realizing positive feedback signal amplification. As a result, ultrasensitive electrochemical detection of nucleic acids was achieved in the dynamic range from 5 aM to 5 fM with a detection limit down to 1.2 aM. There is about 2.5 orders of magnitude improvement in sensitivity compared with the control strategy without homogeneous amplification. Moreover, the proposed strategy was demonstrated with high selectivity, reproducibility, and capability of detecting nucleic acids in serum samples, displaying its promising potential in the development of ultrasensitive electrochemical biosensing platform for disease diagnosis applications.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Kai Wang,Han Yan,Baoshan He,Lingling Xie,Renli Liu,Min Wei,Huali Jin,Wenjie Ren,Zhiguang Suo,Yiwei Xu
Vomitoxin (DON) residues in grains are of great concern to public health. Herein, a label-free aptasensor was constructed to detect DON distributed in grains. Cerium-based metal-organic framework composite gold nanoparticles ( [email protected] ) were used as substrate materials to facilitate electron transfer and provided more binding sites for DNA. The separation of DON-aptamer (Apt) complex and cDNA was achieved by magnetic separation technique based on magnetic beads (MBs), ensuring the specificity of the aptasensor. Exonuclease III (Exo III)-assisted cDNA cycling process strategy would be triggered when cDNA was separated and introduced to the sensing interface for further signal amplification. Under optimal conditions, the constructed aptasensor presented a wide detection range from 1 × 10 −8 mg·mL −1 to 5 × 10 −4 mg·mL −1 for DON, and the detection limit was 1.79 × 10 −9 mg·mL −1 , including a satisfactory recovery in cornmeal sample spiked with DON. The results showed that the proposed aptasensor had high reliability and promising application potential in detecting DON.
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ANALYST
·
2018
·Vol. 143
·期 23
·5771-5778
·
IF 3.864
Xiaolei Song,Yu Wang,Su Liu,Xue Zhang,Haiwang Wang,Jingfeng Wang,Jiadong Huang
In the present work, a simple, rapid, isothermal, and ultrasensitive homogeneous electrochemical biosensing platform for target Hg2+ detection was developed on the basis of an exonuclease III (Exo III)-aided target recycling amplification strategy. In the assay, a label-free hairpin probe (HP1) was ingeniously designed, containing a protruding DNA fragment at the 3′-termini as the recognition unit for target Hg2+. Also, the DNA fragment in the loop region and 5′-termini (Helper) could be used when a secondary target analog is introduced, but it is caged in the stem region of HP1 when without such a target. The produced secondary target Helper opened the methylene blue (MB)-labeled hairpin probe (HP2) and triggered the Exo III cleavage process, accompanied with the secondary target recycling. This accordingly resulted in the autonomous reduction of the electroactive material MB on the electrode, inducing a distinct decrease in the electrochemical signal. The current developed homogeneous strategy provides a means for the ultrasensitive electrochemical detection of Hg2+ down to the 227 pM level, with high selectivity. It could be further used as a general autocatalytic and homogeneous strategy toward the detection of a wide spectrum of analytes and may be associated with more analytical techniques.
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ANALYTICAL SCIENCES
·
2024
·
IF 1.8
Liu Xing,Liu Zhen,Pan Yiliang,Xiao Xilin
Construct a sensitive and rapid detection fluorescence biosensor with the assistance of exonuclease III to achieve efficient detection of Hg 2+ . Nucleic acid aptamer H0 specifically recognizes Hg 2+ , and under the action of exonuclease III, H0 bound to Hg 2+ is hydrolyzed, which in turn fails to trigger the catalytic hairpin self-assembly amplification reaction, resulting in a decrease in the number of double-stranded DNA bound to the fluorescent dye SYBR Green I in the solution, and a decrease in the fluorescence intensity. The results showed that the concentration of Hg 2+ showed a good linear relationship with the fluorescence intensity of the sensing system within the range of 3.8–10 pmol/L, and the detection limit was 0.53 pmol/L. The recoveries of Xiangjiang River water used for the analysis of the actual samples were in the range of 99.57–103.58%, and the relative standard deviations of the determined values were 2.4–3.7%. The method is simple, sensitive, specific, cost-effective and can be applied to water samples. Graphical abstract
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BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Huanshun Yin,Zhiqing Yang,Bingchen Li,Yunlei Zhou,Shiyun Ai
Herein, an electrochemical biosensor was fabricated for DNA demethylase detection based on DNA demethylation triggered endonuclease BstUI and Exonuclease III digestion. After the double-strand DNA was demethylated, it can be further digested by BstUI and formed a blunt end at the electrode surface . Then, the remained fragment of DNA–DNA duplex was further cleaved by exonuclease III and led to increased electrochemical signal. Based on this detection strategy, the biosensor showed high sensitivity with low detection limit of 0.15 ng/mL. Moreover, the developed method also presented high selectivity and acceptable reproducibility. This work provides a novel detection platform for DNA demethylase detection.
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ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Xuehong Min,Mengshi Zhang,Fujian Huang,Xiaoding Lou,Fan Xia
Enzyme-assisted detection strategies of microRNAs (miRNAs) in vitro have accomplished both great sensitivity and specificity. However, low expression of miRNAs and a complex environment in cells induces big challenges for monitoring and tracking miRNAs in vivo. The work reports the attempt to carry miRNA imaging into live cells, by enzyme-aided recycling amplification. We utilize facile probes based yellow aggregation-induced emission luminogens (AIEgens) with super photostable property but without quencher, which are applied to monitor miRNAs not only from urine sample extracts (in vitro) but also in live cells (in vivo). The assay could distinguish the cancer patients’ urine samples from the healthy urine due to the good specificity. Moreover, the probe showed much higher fluorescence intensity in breast cancer cells (MCF-7) (miR-21 in high expression) than that in cervical cancer cells (HeLa) and human lung fibroblast cells (HLF) (miR-21 in low expression) in more than 60 min, which showed the good performance and super photostability for the probe in vivo. As controls, another two probes with FAM/Cy3 and corresponding quenchers, respectively, could perform miRNAs detections in vitro and parts of in vivo tests but were not suitable for the long-term cell tracking due to the photobleach phenomena, which also demonstrates that the probe with AIEgens is a potential candidate for the accurate identification of cancer biomarkers.
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ANALYTICAL CHEMISTRY
·
2016
·
IF 5.886
Caili Fu,Chang Liu,Ying Li,Yajing Guo,Fang Luo,Peilong Wang,Longhua Guo,Bin Qiu,Zhenyu Lin
Abasic site (AP site) in the triplex structure can recognize specific target with high selectivity. In this study, this character was first applied to develop a simple, sensitive, and selective homogeneous electrochemical biosensor for melamine determination. The assay combines the advantage of the high selectivity of the DNA triplex structure containing an AP site to melamine and high efficiency of exonuclease (Exo) III-assisted recycling amplification. DNA-1 (T1), DNA-2 (T2), poly[dA] probe containing an AP site (8A) and methylene blue-labeled DNA probe (dMB probe) were carefully designed. Melamine can specifically locate in the AP site through hydrogen bonding interaction between thymine and melamine to make T1, T2, and 8A close to each other, therefore, forming a stable T-melamine-T DNA triplex structure. Under the optimal conditions, the differential pulse voltammetric (DPV) response had a linear relationship with the logarithm of melamine concentration in the range of 1 nM∼0.5 μM. The developed biosensor has been successfully applied to detect the migration of melamine from melamine bowl. Result showed that the migration in 4% acetic acid solvent was the largest, which is similar to that detected by high performance liquid chromatography. This homogeneous electrochemical sensor may have a potential prospect in detecting melamine in dairy products and migration of melamine from multicategory food packaging or application materials.
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Analytical Methods
·
2025
·
IF 2.6
Lili Zhou,Guangyue Hou,Dan Xi,Yue Guo,Yanping Gou,Hanlin Li,Yaning Zhang,Yongxin Mo,Xiaoli Dai,Rongjin Xu,Hany S. El-Mesery,Wenjie Lu
Mercury ion (Hg²⁺) pollution in tea poses significant risks to human health due to its high toxicity, bioaccumulation, and potential to cause neurological and kidney damage. Sensitive monitoring of Hg²⁺ in tea is therefore critical for food safety and public health. Here, we developed an electrochemical biosensor for ultrasensitive Hg²⁺ assay by integrating thymine-Hg²⁺-thymine (T-Hg²⁺-T) mismatch recognition with exonuclease III (EXO III)-assisted dual signal amplification. The sensing mechanism relies on Hg²⁺-triggered formation of T-Hg²⁺-T structures, which activate EXO III to release Hg²⁺ for cyclic reuse while generating reporter DNA (RDNA). Signal amplification is further enhanced by MOF(Zr)/Th/AuPt nanocomposites, where Zr-based metal-organic frameworks (MOF(Zr)) and AuPt nanoparticles synergistically catalyze thionine (Th) oxidation, producing a strong electrochemical response. This dual-amplification strategy achieves a detection limit of 4.45 pM, surpassing conventional methods. The biosensor demonstrates high specificity against interfering metal ions (e.g., Cd²⁺, Cu²⁺) and reliable performance in real tea samples (93.7%~103.4% recovery), offering a promising tool for monitoring Hg²⁺ contamination in food products.
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ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Xiao-Mei Yan,Yin-Qi Wang,Yao Chen,Zeng-Ping Chen,Ru-Qin Yu
A simple but effective method for the detection of miRNAs was proposed by integrating exonuclease-III assisted target recycling amplification and repeated-fishing strategy. In the proposed method, exonuclease-III assisted target recycling amplification reaction is adopted to produce a large amount of DNA fragments with fluorescence group at its 5′ end in the presence of the target miRNA, which are then repeatedly fished out from the reaction mixture by a gold foil modified with a capture probe and transferred into a so-called ‘product tube’. The amount of the target miRNA can then be determined from the fluorescence measurement of the solution in the ‘product tube’. Application to the detection of miRNA-155 in samples of KH-2 and BRSA-2B cells revealed that the proposed method could achieve sensitive and accurate quantification of the target miRNA with a limit of detection of 36 fM and recovery rates in the range from 96.2% to 105%. Its simplicity, sensitivity and resistance to possible fluorescence interferences in complex biological samples make the proposed method a potentially competitive alternative for miRNAs detection in complex biological samples.
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MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Feng Xu,Xin Chen,Daofei Lv,Yong Liang
Here, we report a DNA hairpin strategy for electrochemical determination of Hg 2+ based on T-Hg 2+ -T pairs and exonuclease III (Exo III) assistance. The innovation of this work lies in the designed DNA structure and detection principles. Unlike the previously reported DNA hairpin structure, the ring portion of the hairpin DNA we designed consisting of T bases serves as a recognition probe, forming a T-Hg-T complex with Hg 2+ . The stem is composed of 5 pairs of complementary bases, which is conducive to the stability of the hairpin structure. After the formation of T-Hg-T in the ring, with the help of Exo III, Exo III can digest more DNA than the T bases designed in the stem. In this event, the shorter the length of the remaining DNA strand on the electrode, the weaker the repulsive force against [Fe(CN) 6 ] 3−/4− , and the stronger the differential pulse voltammetry (DPV) current signal, achieving “signal-on” transitions. Under the optimal conditions, the DPV current response increases with increasing Hg 2+ concentration and is linear with the logarithm of Hg 2+ concentration (1 nM–10 μM). The limit ofdetection is 0.16 nM. The electrochemical sensor was successfully applied to the determination of Hg 2+ in river water.
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RSC Advances
·
2016
·Vol. 6
·期 110
·108662-108667
·
IF 3.289
Jin-Xiu Cao,Yong-Sheng Wang,Jin-Hua Xue,Yan-Qin Huang,Ming-Hui Li,Si-Han Chen,Bin Zhou,Xian Tang,Xiao-Feng Wang,Yu-Feng Zhu
We report on a novel and highly sensitive strategy for UO22+ detection. The designed single-labeled hairpin signal probe (SSP) was employed as a reporter, and a multipurpose RNA-cleaving DNAzyme as a target recognition element, catalytic DNAzyme and the primer of substrate fragment recycling amplification. The presence of UO22+ results in the substrate strand in DNAzyme being cleaved at the RNA site, releasing short substrate fragments. The fragment that is complementary partially with SSP could open the hairpin of SSP to form a double-stranded DNA with recessed 3′-termini, which could be selectively digested by exonuclease III. After the double-stranded DNA is fully consumed, the substrate fragment is released. This one could hybridize with another SSP to initiate the next round of digestion by exonuclease III. The recycling of substrate fragments can be repeated multiple times, resulting in the accumulation of the more 6-carboxyfluorescein in the solution along with an amplified fluorescence signal. By this strategy, we achieved hitherto an unreported UO22+ detection limit of 2.4 pM. Therefore, this novel exonuclease III-amplified strategy has great potential for highly sensitive and selective quantification of UO22+ in biomedical research and environmental science fields.
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