ANALYST
·
2016
·Vol. 141
·期 5
·1830-1836
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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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DOI
PubMed
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Xiuzhong Wang,Ting Hou,Shanshan Dong,Xiaojuan Liu,Feng Li
Pesticides are of great importance in agricultural and biological fields, but pesticide residues may harm the environment and human health. A highly sensitive fluorescent biosensor for the detection of carbamate pesticide has been developed based on acetylcholinesterase (AChE)-catalyzed hydrolysis product triggered Hg 2+ release coupled with subsequent nicking enzyme-induced cleavage of a duplex DNA for cycling amplification. In this protocol, two DNA probes, an unmodified single-stranded helper DNA probe 1 (HP1) and a quencher–fluorophore probe (QFP) are ingeniously designed. HP1 can be folded into hairpin configuration through T–Hg 2+ –T base pair formation. QFP, labeled with FAM and BHQ1 at its two terminals, contains the recognition sequence and the cleavage site of the nicking enzyme . In the presence of carbamate pesticide, the activity of AChE is inhibited, and the amount of the product containing the thiol group generated by the hydrolysis reaction of acetylthiocholine chloride (ACh) decreases, resulting in the release of a low concentration of Hg 2+ . The number of HP1 that can be selectively unfolded would be reduced and the subsequent nicking enzyme-assisted cleavage processes would be affected, resulting in decreased fluorescence signals. The fluorescence intensity further decreases with the increase of the pesticide concentration. Therefore, the pesticide content can be easily obtained by monitoring the fluorescence signal change, which is inversely proportional to the logarithm of the pesticide concentration. The detection limit of aldicarb , the model analyte , is 3.3 μg L −1 , which is much lower than the Chinese National Standards or those previously reported. The as-proposed method has also been applied to detect carbamate pesticide residues in fresh ginger and artificial lake water samples with satisfactory results, which demonstrates that the method has great potential for practical application in biological or food safety field.
研究领域:
分析化学
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环境科学
·
食品安全
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PubMed
高影响因子
JOURNAL OF APPLIED MICROBIOLOGY
·
2019
·Vol. 126
·期 1
·102-112
·
IF 2.683
Lin W.,Yuan D.,Deng Z.,Niu B.,Chen Q.
ObjectivesIn our previous research, we have developed a new combination disinfectant, glutaraldehyde‐didecyldimethylammonium bromide (GD). It was verified that GD had a strong effect on both Escherichia coli and Staphylococcus aureus. In this work, Candida albicans was selected as an object, and it could be killed by GD. We aimed to investigate the cellular and molecular mechanism of GD effecting on C. albicans.Methods and ResultsThe results of sterilization experiment indicated that GD was effective on C. albicans. Flow cytometry and atomic absorption spectrometry were applied to detect cell membrane damage of C. albicans. Luciferase reaction and Bradford method were carried out to detect ATP content and protein quantitation. Transmission electron microscopy was used for intracellular organelles morphological observation. In order to study changes in mitochondrial membrane potential, Rh 123 was used as an indicator. DNA conformation analysis was performed by molecular modelling and circular dichroism. The results indicated that membrane permeability was increased rapidly owing to GD effect, and the leaked K+ and Mg2+ were about 12·1 and 12·4 times those of the control, respectively, at 10 min after GD treatment. Simultaneously, ATP and protein also leaked rapidly out of the cell. Mitochondrial membrane potential was destroyed, succinic dehydrogenase activity was significantly decreased and DNA conformation was changed because of GD action.ConclusionsGlutaraldehyde‐didecyldimethylammonium bromide disinfected C. albicans through distorting cell membrane integrity and permeability, disturbing the intracellular homeostasis by intracellular substances leakage, especially K+, Mg2+, ATP and protein, causing electrolyte imbalance of mitochondria, changing DNA structure, which finally led to cell death.Significance and Impact of the StudyThis study focused on the cellular and molecular mechanism of GD as a disinfectant against C. albicans. It is important to provide theoretical support to GD against Candida albicans in practical application.
研究领域:
微生物学
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分子生物学
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细胞生物学
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PubMed
高影响因子
LUMINESCENCE
·
2022
·Vol. 37
·期 11
·1964-1971
·
IF 2.613
Long Bai,Tai Ye,Dongdong Zhu,Donghao Sun,Shuyi Zhang,Yujie Lu,Min Yuan,Hui Cao,Liling Hao,Xiuxiu Wu,Fengqin Yin,Fei Xu
The improper conformation of oligonucleotides on gold nanoparticle surfaces is caused by unintended base adsorption, which hinders DNA hybridization and lowers colloidal stability. In this work, we treated spherical nucleic acids with Br − , which serves as an efficient backfilling agent, to adjust the DNA conformation by displacing bases from the gold surface. To investigate the effect of DNA conformation on interfacial recognition, a kanamycin fluorescent aptasensor was constructed with bromide backfilled-treated spherical nucleic acids. In the presence of kanamycin, the anchored aptamer binds with the target and the partially complementary reporter strand is dissociated from the surface of the gold nanoparticles, resulting in the fluorescence recovery of labelled fluorophore on the reporter strand. Under optimum conditions, the apparent binding affinity of the aptasensor with bromide backfilling was 2.2-fold that without backfilled one. The proposed aptasensor exhibited a good liner relationship between the concentration of kanamycin and fluorescence intensity change in the range 200 nM to 10 μM and the limit of detection was calculated to be 71.53 nM. Moreover, this aptasensor was also successfully applied in a spiked milk sample assay and the satisfactory recoveries were obtained in the range 96.94–101.57%, which demonstrated its potential in practical applications.
研究领域:
纳米技术
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分析化学
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生物传感器
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药物检测
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DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Lihua Lu,Huijuan Su,Qingyun Liu,Feng Li
To improve the G-quadruplex specificity of Ir(III) complexes, a novel dinuclear Ir(III) complex (Din Ir(III)–1) was designed and synthesized through connecting two mononuclear Ir(III) complexes via a diphenyl bridge. Din Ir(III)–1 presents 3.4–4.1-fold enhancements for G-quadruplex relative to ssDNA and 4.3–5.3-fold enhancements relative to dsDNA in luminescence intensity, respectively, demonstrating an excellent G-quadruplex selectivity. Ascribed to its superior specificity to G-quadruplex, Din Ir(III)–1 was employed to construct a highly sensitive luminescent pesticides’ detection platform. The detection is based on acetylcholinesterase (AChE)-catalyzed hydrolysis product-induced DNA conformational transformation and subsequent terminal deoxynucleotidyl transferase (TdT) directed G-quadruplex formation. The assay exhibited a linear response between the emission intensity of Din Ir(III)–1 and the pesticide concentration in the range of 0.5–25 μg/L (R2 = 0.994), and the limit of detection for the pesticide was as low as 0.37 μg/L when using aldicarb as the model pesticide. Moreover, this strategy demonstrates good applicability for the pesticide detection in real samples. It is also versatile for the detection of other organophosphate or carbamate pesticides, which have the inhibition ability toward AChE. Therefore, the proposed approach is scalable for practical application in food safety and environmental monitoring fields and will provide promising solutions for the assay of pesticide residues.
研究领域:
分析化学
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材料科学
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环境科学
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食品科学
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PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2024
·
IF 6.7
Hang Ao,Wencheng Xiao,Wenrui Hu,Jie Wu,Huangxian Ju
This work designed a DNA conformation-regulated hemin switch for rapid chemiluminescent (CL) detection of a monoclonal antibodies. This switch was performed with an affinity probe and an inhibition probe, which were conveniently prepared by hybridizing hemin-labeled DNA1 with KHL peptide-labeled DNA2 and binding biotin-labeled DNA3 to streptavidin, respectively. In the absence of the target antibody, streptavidin-DNA3 could hybridize with hemin-DNA1/KHL-DNA2 to release KHL-DNA2, which led to the loss of hemin activity due to the affinity hindrance of streptavidin-DNA3. After the KHL peptide was recognized by the target antibody, the strand replacement hybridization could be inhibited by the bound antibody, which retained the high catalytic activity of hemin overhung on the antibody-bound affinity probe for a CL reaction, leading to a “signal-on” process for CL antibody detection. Using a KHL-specific antibody, anti-proprotein convertase subtilisin/kexin type 9 antibody (PCSK9-Ab), as a target model and common L012–1,2,4-triazole–H2O2 CL system, the designed switch showed a detection range of 10 ng mL–1 to 1 μg mL–1 with a detection limit of 4.16 ng mL–1 (56.2 pM) and a short analytical time of 6.5 min. The proposed quick method could simply be used for lab-on-chip CL detection of PCSK9-Ab in situ-secreted from PCSK9-6E3 hybridoma cells, which showed an accuracy of 90.2% compared with the statistical results from general fluorescence imaging, providing a potential technique for screening specific hybridoma cells.
研究领域:
生物化学
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分析化学
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生物技术
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分子生物学
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DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Rui Wang,Na Li,Xing Hu,Junhui Pan,Guowen Zhang,Xinan Zeng,Deming Gong
The binding characteristics of food antioxidant tert -butylhydroquinone (TBHQ) and its oxidation product tert -butylquinone (TBQ) with calf thymus DNA (ctDNA) in vitro were investigated using multispectroscopy, chemometrics , viscosity measurements, gel electrophoresis assays and molecular docking . Analysis of fluorescence spectra found that TBHQ and TBQ bound with ctDNA to form 1:1 complexes with the binding constant in the order of 10 4 L mol −1 . The concentration profiles and the pure spectra for the components (TBHQ, TBQ, ctDNA and TBHQ– or TBQ–ctDNA complex) were obtained through analyzing the expanded ultraviolet-visible absorption data matrix by multivariate curve resolution–alternating least squares algorithm, which successfully monitored the binding process of TBHQ/TBQ with ctDNA. Fluorescence displacement, viscosity and molecular docking experiments showed that TBHQ bound to ctDNA through intercalation binding, while TBQ bound to the minor groove of ctDNA. The binding of TBHQ to ctDNA induced the conversion of DNA conformation from B-form to A-form, while TBQ caused a minor perturbation on the DNA conformation. Gel electrophoresis results indicated that the combination of TBHQ and Cu(II) could induce DNA damage. This study may contribute to understanding the binding mechanisms of TBHQ and TBQ with ctDNA and further evaluate the potential toxicological effects of TBHQ as a food additive .
研究领域:
生物化学
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分子生物学
·
毒理学
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食品科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）