FOOD CHEMISTRY
·
2022
·
IF 9.231
Jiaqi Wang,Lei Tan,Wenchao Bi,Haoyu Shen,Dengfeng Li,Zhenzhong Yu,Ning Gan
This work demonstrated an ultrasensitive and simple microfluidic immunosensor for point-of-care test of Staphylococcus aureus ( S. aureus ) based on the stir bar enrichment and DNAzyme-assisted click reaction. Initially, S. aureus was enriched by the 4-mercaptophenylboronic acid-functionalized stir bar. The yolk antibody (immunoglobulin Y) and copper-labeled polydopamine nanoparticles were then specifically conjugated with the captured target. The Cu(II) was released under acidic conditions and effectively catalyzed the copper-catalyzed azide-alkyne cycloaddition (CuAAC) between the alkyne group-labeled DNAzyme and the streptavidin–biotin-azido with the assistance of DNAzyme. Finally, the DNAzyme-streptavidin complexes were detected by microfluidic chips to quantify S. aureus . Under optimum conditions, this immunosensor showed good detection performances toward S. aureus within 10 to 2.5 × 10 4 CFU/mL with a limit of detection of 3 CFU/mL. Moreover, the satisfying detection results of real samples of animal origin also implied that this immunosensor owned great potential in practical applications.
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Journal of Materials Chemistry B
·
2015
·Vol. 3
·期 24
·4805-4813
·
IF 4.726
Rong Tian,Xiaojun Chen,Nan Jiang,Ning Hao,Lin Xu,Cheng Yao
A highly sensitive electrochemical sensor for the detection of mercury(II) ions (Hg2+) was developed by using a three dimensional ordered macroporous polyaniline–platinum (3DOM PANI–Pt) composite film as a sensing platform. 3DOM PANI–Pt was realized by electrochemical co-deposition of Pt nanoparticles and PANI into the sacrificed silica template through the redox reaction involving the monomer aniline (AN) and PtCl62−. The G-rich oligonucleotide strand functionalized Au nanoparticle was employed as the Hg2+-mediated structural switch and to enhance the sensitivity. In the absence of Hg2+, the oligonucleotide strand formed an intramolecular duplex where the G-rich sequence was partially caged. In the presence of Hg2+, the release of the G-rich sequence was observed due to the stabilization of T–Hg2+–T, which formed an active G-quadruplex DNAzyme and catalyzed the reduction of H2O2. Under the optimal conditions, the current signal of H2O2 increased with increasing Hg2+ concentration in the dynamic range from 10−13 to 10−6 M, and the detection limit up to 8.7 × 10−14 M was seen. Further, the sensor was successfully utilized for the determination of Hg2+ in an authentic aquatic sample, with an acceptable accuracy compared to the method commercially available. In this paper, we proposed a general and simple strategy because only one oligonucleotide strand was required for both Hg2+ recognition and signal amplification, potentially allowing the detection of other metal ions or trace pollutants in environmental matrices by simply employing various DNA or aptamer probes.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Jing-Yi Huang,Lang Zhao,Wan Lei,Wei Wen,Yi-Jia Wang,Ting Bao,Hua-Yu Xiong,Xiu-Hua Zhang,Sheng-Fu Wang
In this work, we have developed an electrochemical aptasensor for high-sensitivity determination of carcinoembryonic antigen (CEA) based on lead ion (Pb 2+ )-dependent DNAzyme-assisted signal amplification and graphene quantum dot-ionic liquid-nafion (GQDs-IL-NF) composite film. We designed hairpin DNA containing CEA-specific aptamers and DNAzyme chains. In the presence of CEA, hairpin DNA recognized the target and performed a DNAzyme-assisted signal amplification reaction to yield a large number of single-stranded DNA. The GQDs-IL-NF composite film was immobilized on the glassy carbon electrode for the interaction with single-stranded DNA through noncovalent π-π stacking interaction. Therefore, the methylene blue-labeled substrate DNA (MB-substrate) was fixed on the electrode and exhibited an initial electrochemical signal. Under optimal conditions, the response current change was proportional to the concentration of CEA, demonstrating a wide linear range from 0.5 fg mL −1 to 0.5 ng mL −1 , with a low detection limit of 0.34 fg mL −1 . Furthermore, the proposed aptasensor was successfully applied in determining CEA in serum samples, showing its superior prospects in clinical diagnosis.
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Analytical Methods
·
2017
·Vol. 10
·期 1
·51-58
·
IF 1.9
Xiao-Li Du,Tian-Fang Kang,Li-Ping Lu,Shui-Yuan Cheng
A novel electrochemiluminescence (ECL) biosensor based on CdSe@CdS quantum dots (QDs) functionalized MoS2 modified electrode was developed for sensitive detection of Pb(II) using HRP-mimicking DNAzyme biocatalytic precipitation (BCP) for ECL signal quenching. Polycationic poly(diallyldimethylammonium chloride) (PDDA) and negatively charged QDs were adsorbed on the surface of MoS2, in sequence, to form the MoS2–QDs composites, which were employed as a matrix for the immobilization of the G-rich DNA strand, i.e., T30695. The MoS2–QDs were characterized by UV-vis absorption spectroscopy, fluorescence spectroscopy, energy dispersive spectrometry, transmission electron microscopy, and field emission scanning electron microscopy. CdSe@CdS QDs can produce an ECL signal using 0.1 M K2S2O8 as a co-reactant. T30695 can combine with Pb(II) ions to form a stable parallel G-quadruplex. The G-quadruplex can further combine with hemin to form DNAzyme, which can catalyze H2O2 and oxidize 4-chloro-1-naphthol (4-CN) to produce an insoluble precipitation of benzo-4-chlorohexadienone on the surface of the sensor. When the concentration of Pb(II) in the solution was increased, more of DNAzyme was generated and subsequently more 4-CN molecules were oxidized catalytically, leading to a decrease of the ECL signal. Using this quenching strategy, the ECL signal of the biosensor was linearly dependent on the logarithm of the Pb(II) concentration ranging from 1.0 × 10−15 to 1.0 × 10−11 M with a detection limit of 0.98 f M. The stability and selectivity of the sensor were also investigated. The sensor was applied in the determination of Pb(II) in the real water samples and satisfactory results were obtained.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Wenshan Li,Qingqing Li,Huaiyue Xia,Wenjie Liu,Guoxing Jing,Jianna Yu,Wen Liu,Mengtong Lin,Yujuan Huang
Ochratoxin A (OTA) is a compound of concern due to its potential health effects on humans. Detecting OTA in food is crucial for safeguarding public health. In this study, we fabricated a multi-DNAzyme cascade reaction-mediated colorimetric aptasensors for OTA detection, integrating autocatalytic Mg 2+ -dependent DNAzyme cleavage (MNAzyme) and an entropy-driven circuit. In brief, the recognition between the aptamer and target OTA led to the release of DNA1. Subsequently, DNA1 hybridized with DNA2, generating an upstream MNAzyme that facilitated the production of a downstream MNAzyme. These MNAzymes possess similar substrate binding arms, enabling them to catalyze the same substrate. The catalytic efficiency of MNAzymes towards the substrates was enhanced due to the increasing concentration of MNAzymes. The cleavage products then triggered an entropy-driven cycle to generate a signal. Under optimal conditions, the sensing system exhibited low detection limits of 48.97 fM for OTA. Additionally, the proposed aptasensor was successfully applied to quantitatively analyze OTA in food samples. Thus, the multi-DNAzyme cascade reaction-mediated colorimetric aptasensors offer an adaptable platform for detecting traces of OTA contaminant in food.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2026
·
IF 8.3
Han Zhang,Zhen Zhao,Jing Zhang,Yonghua Wang,Yuanzhu Liu,Leyi Xiao,Tengye Zhang,Cheng Sun,Yusheng Niu,Yubing Liu,Dengshuo Liu,Qin Wen,Lu Wang,Yuanhong Xu
Accurate recognition and capture of circulating tumor cells (CTCs) remain challenging due to their extreme rarity and heterogeneity. Strategies based on logical analysis of multiple surface markers offer inherent advantages in specificity but often suffer from insufficient sensitivity. Herein, we report an intelligent colorimetric platform integrating enrichment and detection via dual aptamer recognition strategy-mediated proximity-induced in situ assembly of tandem G4 DNAzymes using MCF-7 breast cancer cells as a CTC model. The platform employs two aptamers that specifically recognize EpCAM and MUC1, two membrane-associated protein markers overexpressed on MCF-7 cells. Upon simultaneous recognition of two distinct membrane proteins on CTCs, the DNAzymes cooperatively assemble on the cell surface, enabling cascade signal amplification without exogenous enzymes and executing an AND logic gate. By coupling a micropore membrane-based enrichment device with a portable smartphone-assisted colorimetric readout system, the system achieves a detection limit as low as 2 cells/mL and a linear range of 10 - 5 × 10 4 cells/mL. Leveraging the dual-aptamer logic gate, it accurately distinguishes target cell subtypes from heterogeneous populations based on the presence or absence of specific biomarkers. Spike recovery in blood samples ranges from 95.42% to 107.26%, and visual quantitative analysis is completed within 10 min. This work provides a promising strategy for liquid biopsy by combining high sensitivity, intrinsic specificity, and operational simplicity in a compact, integrated format.
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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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FOOD CHEMISTRY
·
2023
·
IF 8.8
Wenju Yan,Xuefei Qin,Xueqing Sang,Xueying Zhou,Yanying Zheng,Yali Yuan,Yun Zhang
A dual-mode sensing platform for Pb 2+ was constructed based on the dual optical channels of Au NPs system with the amplification of DNAzyme, and it was successfully applied for Pb 2+ determination in preserved egg with satisfactory results. The presence of Pb 2+ activated the DNAzyme and induced the dispersion change of Au NPs in high salt concentration. The sequent absorption change of Au NPs was translated to the fluorescence change of carbon dots through FRET, and the scattering change was transferred to grey value of images involving the Tyndall effect. Thus, a sensing platform based on fluorescence and colorimetric dual-technique was achieved for Pb 2+ detection, under the optimized conditions. With the assistance of DNAzyme, the linear range of fluorometric and colorimetric method were 2.0 × 10 -14 ∼ 8.0 × 10 -10 mol/L and 2.4 × 10 -13 ∼ 9.5 × 10 -9 mol/L, respectively. The dual-mode sensing platform demonstrated its promising application in the environmental monitoring and food safety field.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 2
·1-8
·
IF 6.232
Li Ruiying,Liu Qiang,Jin Yan,Li Baoxin
The authors have incidentally found that the three tandem repeats of a 13-mer G-rich oligomer (with sequence 5′-TGG GAA GGG AGG G-3′; referred to as G3) can directly fold into a stable G3 trimer. The G3 trimer/hemin DNAzyme exhibits an about 3-fold higher peroxidase-mimicking activity compared to the conventional G3/hemin DNAzyme. Combining this finding with rolling circle amplification (RCA), a colorimetric assay was developed for sensitive and specific determination of microRNA. In this method, each cycle of RCA generates three catalytic units. This leads to a significant signal amplification of the RCA. Using let-7a as a model analyte, the colorimetric method (best performed at 420 nm) exhibits high sensitivity toward microRNA-let-7a with a 37 fM detection limit and an analytical range that covers 3 orders of magnitude. The method was applied to the determination of let-7a in some cell lysates.
This G-triplex trimer-based rolling circle amplification (RCA) method can produce three catalytic units per RCA cycle, which can significantly improve the amplification efficiency of RCA.
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MICROCHIMICA ACTA
·
2025
·Vol. 192
·期 6
·1-12
·
IF 5.3
Chen Yafei,Zhang Xuhui,Huang Wanjin,Jin Zhenhuan,Wei Xiaoping,Li Jianping
Atrazine (ATZ) is used extensively, resulting in residues in food and the environment, posing a serious threat to human health. Herein, Cd 0.5 Zn 0.5 S/Ti 3 C 2 photoelectric material was synthesized and immobilized on a FTO electrode as a photoanode. A photoelectrochemical (PEC) aptamer sensor was constructed for the highly sensitive and selective determination of ATZ based on signal amplification via cascade catalysis of CRISPR/Cas12a and G-quadruplex/hemin DNAzyme (G4/hemin DNAzyme). G4/hemin DNAzyme catalyses the oxidation reaction between H 2 O 2 and dopamine (DA) to form polydopamine (PDA) deposit. This process, in turn, inhibits the photocurrent at the photoanode, leading to a decrease in photocurrent. Concurrently, the depletion of DA as an electron donor for the PEC reaction at the photoelectrode further contributes to the decrease in photocurrent. ATZ can hybridize with ATZ aptamer (Apt) in Apt/cDNA to release activation strand (cDNA), which activates the activity of CRISPR/Cas12a and triggers cleavage of G4, causing the cleaving of G4/hemin DNAzyme immobilized on the electrode surface. This process leads to a decrease of G4/hemin DNAzymes amount on the electrode, consequently reducing both the PDA generation and the DA consumption. As a result, the photocurrent is restored. The cascade catalysis of CRISPR/Cas12a and G4/hemin DNAzyme has been demonstrated to result in photocurrent amplification. The photocurrent change was linear with the logarithmic value of ATZ concentration in the range 1.00 × 10 –12 to 1.00 × 10 –5 mol/L. The limit of detection was 3.47 × 10 –13 mol/L. The sensor has been successfully applied to the determination of trace ATZ in environmental and food samples. Graphical abstract
研究领域:
环境科学
·
分析化学
·
分子生物学
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Peipei Song,Zhirui Fan,Shuai Sun,Chengye Sun,Jun Wang
In recent years, lead (Pb) contaminated soil has caused irreversible damage to human beings. It is urgent to develop a novel technology for accurate detection of Pb in the soil solution. Herein, a new electrochemical sensor was fabricated. Fe/ZIF-8 was used as the modification material, gold nanoparticles (AuNPs) were electrodeposited, and DNAzyme was applied on the surface as the probe. Under the optimum conditions (DNAzyme concentration of 1 μmol, fixation time of 4 min, incubation time of 17 h and reaction time of 30 min), the detection range was 5×10 −12 ∼ 5×10 −5 M, and the minimum detection limit was 10 −13 M (3δ). Furthermore, the electrochemical sensor demonstrated outstanding anti-interference ability to common cations, anions, organic compounds and other interference factors. After four consecutive tests, the relative standard deviation (RSD) was only 0.39%, and it still displayed excellent reproducibility with 0.69% of RSD. After 20 days, the sensor’s response to Pb 2+ remained at 93.58%. In addition, the sensor could accurately detect Pb 2+ in the actual soil solutions, and the recoveries of the samples ranged from 92% to 109.4%. In conclusion, this electrochemical sensor can specifically detect Pb 2+ in the soil solution with enhanced sensitivity, anti-interference capability and stability, which is of great significance for Pb 2+ detection in the field.
研究领域:
环境科学
·
分析化学
·
纳米技术
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ANALYTICA CHIMICA ACTA
·
2023
·
IF 6.2
Yuanyuan Yue,Songtao Wang,Qiang Jin,Nan An,Lina Wu,He Huang
Lead ions (Pb 2+ ) are a well-known toxic heavy metal that poses a significant threat to human health. Therefore, the development of a simple and ultrasensitive technique for detecting Pb 2+ is essential. With their trans -cleavage properties, the newly discovered CRISPR-V effectors have become a potential high-precision biometric tool. In this regard, a CRISPR/Cas12a-based electrochemical biosensor (E-CRISPR) has been developed, which is combined with the GR-5 DNAzyme that can specifically recognize Pb 2+ . In this strategy, the GR-5 DNAzyme acts as a signal-mediated intermediary, which can convert Pb 2+ into nucleic acid signals, thereby becoming single-stranded DNA that triggers strand displacement amplification (SDA) reaction. This is coupled with following activated CRISPR/Cas12a cleavage of the electrochemical signal probe, enabling cooperative signal amplification for ultrasensitive Pb 2+ detection. The proposed method has a detection limit as low as 0.02 pM. Therefore, we have developed an E-CRISPR detection platform with GR-5 DNAzyme as a signal medium (called SM-E-CRISPR biosensor). This provides a method for the CRISPR system to specifically detect non-nucleic substances by converting the signal using a medium.
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