TALANTA
·
2018
·
IF 4.244
Li Zou,Tingting Li,Ruidi Shen,Shaozhi Ren,Liansheng Ling
A label-free light-up fluorescent sensing strategy using hybridization chain reaction (HCR) amplification and DNA triplex assembly has been developed. Remarkably, the proposed fluorescence assay is successfully applied to the determination of avian influenza A (H7N9) virus DNA and thrombin. Herein, in the presence of targets, the target DNA/initiator triggers a cascade of hybridization events between H1 and H2 that yields nicked double helices analogous to alternating copolymers . With the additions of triplex-forming oligonucleotide (TFO) and berberine , the triplex structures form between HCR products and TFO. Then, a large amount of berberine can bind to the triplex structures and the sensing system exhibits a dramatic increase in the fluorescence intensity at 530 nm. Under optimal conditions, the label-free fluorescent sensing platform shows sensitive responses to H7N9 virus DNA and thrombin in the range of 0.2–100 nM and 0.5–200 nM, respectively. The detection limits of H7N9 virus DNA and thrombin are as low as 0.14 nM and 0.32 nM, respectively. Owing to the simplicity and low cost, the proposed strategy can be used in other biomarkers assays, providing a promising tool for clinical diagnosis and biomedical detection.
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高影响因子
RSC Advances
·
2018
·Vol. 8
·期 36
·20295-20303
·
IF 2.936
Qiaomei Sun,Zili Suo,Hongyu Pu,Peixiao Tang,Na Gan,Ruixue Gan,Yuanming Zhai,Xiaohui Ding,Hui Li
Thiabendazole (TBZ) is a commonly used food preservative and has a wide range of anthelmintic properties. In this study, computer simulations and experiments were conducted to investigate the interaction mechanism of TBZ and herring sperm DNA (hsDNA) at the molecular level. Molecular docking showed that TBZ interacted with DNA in groove mode and bound in A-T and C-G base pair regions. Molecular dynamics (MD) was used to evaluate the stability of the TBZ–DNA complex and found that the three phases in MD and the hydrogen bonds helped maintain the combination. NMR relaxation indicated that TBZ had a certain affinity to hsDNA with a binding constant of 462.43 L mol−1, and the thiazole ring was the main group bound with DNA. Results obtained from fluorescence experiments showed that the binding of TBZ and hsDNA was predominantly driven by enthalpy through a static quenching mechanism. Circular dichroism and viscosity measurements proved the groove binding mode. The FTIR results clarified the conformational changes of DNA, that the DNA helix became shorter and compact, and the DNA structure transformed from B-form to A-form.
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高影响因子
EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
·
2018
·
IF 4.816
Yumei Li,Qiong Wu,Gengnan Yu,Li Li,Xuanhao Zhao,Xiaoting Huang,Wenjie Mei
In this study, four polypyridyl ruthenium(II) complexes, namely, [(L 1 ) 2 RuL 2 ]·2ClO 4 ( 1 : L 1 = phen, L 2 = o -TFPIP, 2 : L 1 = bpy, L 2 = o -TFPIP, 3 : L 1 = phen, L 2 = o -MOPIP, and 4 : L 1 = bpy, L 2 = o -MOPIP), were synthesized with different phenanthroimidazole derivatives, and their inhibitory activities were tested against various cancer cells. Among the Ru(II) complexes, 1 excellently inhibited the proliferation and induced the apoptosis of HepG2 cell. Importantly, 1 was mainly distributed in the cell mitochondria and markedly induced the dissipation of mitochondrial membrane potential , possibly attributing to DNA damage induced by the Ru(II) complexes. Synthetic Ru(II) complexes can suppress the growth of tumor cells in zebrafish xenograft model with low toxicity at effective concentrations. These results inspired us to further develop polypyridyl ruthenium(II) complexes as potential potent inhibitors against liver cancer.
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高影响因子
MICROCHEMICAL JOURNAL
·
2018
·
IF 2.746
Lili Yu,Hui Xu,Hou Chen,Shengxiao Zhang,Tingting Jiang,Liangjiu Bai,Wenxiang Wang,Shanmin Gao,Juan Jin
A label-free DNA Y junction sensor for amplified detection of Hg 2+ has been demonstrated by using thymine-Hg 2+ -thymine (T-Hg 2+ -T) recognition, cascade toehold-mediated DNA strand displacement and dye staining double-stranded DNA (dsDNA). In our work, assistant DNA could bind with the first hairpin DNA with toehold domains by the help of thymine-Hg 2+ -thymine (T–Hg 2+ –T) base pairs recognition. The second hairpin DNA with toehold domains will then hybridize with the complementary sequences in first hairpin DNA, which again initiates a new toehold domains to open the third hairpin DNA, triggering a cascade strand displacement reaction. Exonuclease III (Exo III) was added to digest the three hairpin DNA with recessed 3′ ends in the absence of Hg 2+ to reduce the background signal. As a comparison, Exo III is replaced by GO to reduce the background signal because single-strand DNA (ssDNA), three hairpin DNAs with intercalated dye could be adsorbed onto the surface of GO and lead to quenched fluorescence. The method, designed in a simple “mix, incubate, and detect” format, can detect concentrations of Hg 2+ as low as 0.031 nM, and exhibit good selectivity and practical application.
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TALANTA
·
2018
·
IF 4.244
Fen Ma,Yu Chen,Yinchang Zhu,Jiawei Liu
A new electrogenerated chemiluminescence (ECL) biosensor is fabricated for the determination of mental ion incorporating DNA three-way junction structure (DNA-TWJ). As a model system, Hg 2+ was chosen as an analyte. The ECL biosensor was fabricated by covalently coupling Hg 2+ special DNA-TWJ tagged with ruthenium (II) complex (Ru) (named TW/Ru-J1) to the surface of glassy carbon electrode that had been covalently modified with 4-aminobenzoic acid via electrochemical oxidations . Upon binding of Hg 2+ to the TW/Ru-J1, the confirmation of TW/Ru-J1 changed and induced Ru away from surface of electrode and thus led to a low ECL signal. The signal linearly decreases with the concentration of Hg 2+ in the range from 0.1 pM to 10 pM with a detection limit of 0.04 pM This study could be easily extended to various analytical platforms for the detection of many kinds of analytes or their interactions such as DNA/RNA, DNAzyme/target, aptamer/target, and antibody/antigen.
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TALANTA
·
2018
·
IF 4.244
Hongbin Pu,Xiaohui Xie,Da-Wen Sun,Qingyi Wei,Yingfen Jiang
A detection method for 17β-estradiol (E2) using surface-enhanced Raman scattering (SERS)-based aptamer sensor was presented. Raman reporter molecule Cy3 labeled E2-aptamer and DNA functionalized gold-silver core-shell nanoparticles ( [email protected] CS NPs) offered SERS with high sensitivity and selectivity . Based on the fabricated double strand DNA-immobilized gold-silver core-shell nanoparticles ( [email protected] NPs), SERS signal intensity of Raman reporter changed with the number of Cy3-labeled aptamer attached to the core-shell nanoparticles due to the strong binding affinity between the aptamers and E2 with different concentrations. A wide linear range from 1.0 × 10 –13 to 1.0 × 10 −9 was obtained for the detection of E2, with a low detection limit of 2.75 fM. This proposed method showed highly sensitive and selective for detecting E2, and could be used to determine E2 in actual samples.
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RSC Advances
·
2014
·Vol. 5
·期 12
·9123-9129
·
IF 3.708
Fenglei Gao,Yan Du,Jingwen Yao,Yanzhuo Zhang,Jian Gao
We developed a novel dual-amplification strategy for ultrasensitive electrochemical detection of DNA based on exonuclease III-assisted target recycling and rolling circle amplification (RCA). In this assay, a gold electrode was used to immobilize a molecular beacon (MB) with a 3′ overhang as recognition probe and perform the dual signal amplification procedure. In the presence of target DNA, MB hybridized with the target DNA to form a duplex region and created a 3′-blunt end for Exo III to initiate the target DNA recycling amplification process to cleave numerous MB probes. Then, the remaining MB fragments hybridized as primers with the RCA template to initiate the RCA process. Subsequently, the detection probe's modified Ag NPs hybridized with the long, amplified DNA products, resulting in the multiplication of Ag NPs on the electrode surface, which were used for subsequent electrochemical strip analysis of silver. This novel signal amplification strategy could detect target DNA down to 6.4 amol L−1, with a dynamic range spanning five orders of magnitude. In addition, this method avoids the de-oxygenation procedure in standard electrochemical detection, thus presenting a promising application in clinical diagnosis.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2014
·
IF 2.871
Chen Zhang,Shichao Xu,Xueping Zhang,Dandan Huang,Runlan Li,Shihuai Zhao,Bing Wang
In this article, we developed an electrochemical method for detection of specific DNA sequences of bladder cancer cells based on CdTe quantum dots (QDs) modified glassy carbon electrode (GCE). Methylene blue (MB) was intercalated into the hybridized double stranded DNA (dsDNA) and used as electrochemical indictor. CdTe QDs amplified the electrochemical signals due to their larger surface area, which can immobilize more single stranded DNA (ssDNA) probes on electrode surface. The morphology and optical properties of CdTe QDs were characterized by transmission electron microscope (TEM), X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), fluorescence spectra (FS), UV–vis spectrum and Fourier transform infrared spectrum (FTIR). Moreover, target DNA was detected by differential pulse voltammetry (DPV) quantitatively. The linear range was obtained from 1 × 10 −12 M to 1 × 10 −8 M, and the limit of detection was 6.435 × 10 −13 M (3δ). The control experiments were also carried out by hybridization with various mismatched DNA sequences. These results displayed this fabricated electrochemical DNA biosensor was of good selectivity, sensitivity, stability and easy operation.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2014
·
IF 3.84
Wanjun Liang,Zhengqing Liu,Shaopu Liu,Jidong Yang,Youqiu He
A kind of novel Glyp-functionalized-CdTe/CdS Quantum dots (QDs) was successfully synthesized by coating Glyp on the surface of the CdTe/CdS QDs. The fluorescence emission of the modified QDs was enhanced greatly but with a low resonance Rayleigh scattering (RRS). When it interacted with calf thymus DNA (ct-DNA), the fluorescence intensity of the system was obviously quenched and the RRS was enhanced, both in good linear relations. Based on the above, a novel fluorescence biosensor for simple, sensitive and selective detection of ct-DNA was developed. Under the optimized conditions, the linear ranges of the functionalized QDs fluorescence intensity and RRS intensity versus the concentration of ct-DNA were 0.109–70 μg mL −1 and 0.482–90 μg mL −1 , respectively. The corresponding detection limits by fluorescence quenching and by RRS enhancing methods were 0.0327 μg mL −1 and 0.146 μg mL −1 , respectively. The proposed method was applied to detect ct-DNA in synthetic sample with satisfactory results.
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ANALYST
·
2015
·Vol. 140
·期 6
·2029-2036
·
IF 4.107
Xiaorong Gan,Huimin Zhao,Shuo Chen,Xie Quan
An ultrasensitive methodology was successfully developed for the quantitative detection of picomolar Hg2+ based on the combination of thymine–Hg2+–thymine (T–Hg2+–T) coordination chemistry and exonuclease III-aided recycling signal amplification. Single-strand probe DNA was immobilized on an Au electrode via an Au–S bond. In the presence of Hg2+, the probe DNA hybridized with the target DNA containing four thymine–thymine (T–T) mismatches via the Hg2+-mediated coordination of T–Hg2+–T base pairs. Then the probe DNA in the DNA duplex was specifically recognized and selectively digested by exonuclease III; in contrast the target DNA was safely dissociated from the DNA duplexes to subsequently hybridize with a new signal probe, leading to target recycling and signal amplification. As a result, the peak current caused by the electrostatic interactions of [Ru(NH3)6]3+ cations with the backbone of the probe DNA decreased by different degrees, corresponding to the Hg2+ concentrations. Under the optimum conditions, the proposed electrochemical DNA biosensor showed a robust detection limit as low as 1 pM (S/N = 3), with a wide linear range from 0.01 to 500 nM and good selectivity. In addition, the proposed method was successfully applied to assay Hg2+ in real environmental samples.
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Fen-Ying Kong,Wei-Wei Li,Jing-Yi Wang,Wei Wang
Herein, we report, for the first time, the synthesis of reduced graphene oxide–DNA–Ag (RGO–DNA–Ag) nanohybrids by ultraviolet (UV) irradiation of aqueous solutions of GO and Ag ions in the presence of DNA . The morphology and microstructure characterizations of the resultant nanohybrids reveal that the proposed method leads to the simultaneous reduction of GO and Ag ions together with efficient dispersion of Ag nanoparticles on the surface of RGO sheets. This simple and fast synthesis route is carried out at ambient conditions without using any additional chemical reducing agents, which has the potential to provide new avenues for the green fabrication of various RGO-based nanomaterials . Additionally, the RGO–DNA–Ag nanohybrids can be utilized as a novel sensing interfacial for direct determination of iodide by simple differential pulse voltammetry (DPV), without requiring any preceding preconcentration of the analyte. Based on the RGO–DNA–Ag nanohybrids modified electrode , a wide linear range of 1 μM–1 mM and a low detection limit of 0.2 μM were obtained. This sensitive and direct method of analysis can be applied successfully to the determination of iodide in real samples.
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ANALYTICAL CHEMISTRY
·
2014
·
IF 5.825
Yan Wang,Jian Chen,Yang Chen,Wenying Li,Cong Yu
A new label-free strategy for sensitive fluorometric biosensing based on perylene probe monomer–excimer transition has been developed. A negatively charged perylene probe (compound 1) was used. Compound 1 shows strong monomer fluorescence in an aqueous buffer solution. A cationic polymer could induce aggregation of compound 1 through noncovalent interactions. Compound 1 monomer emission was quenched, and meanwhile strong excimer emission was observed. Upon addition of a single-stranded DNA (an anionic polymer), strong electrostatic attractive interactions between the cationic polymer and the DNA weakened the binding of aggregates of compound 1 to the polycation. Compound 1 monomers were released, and excimer–monomer emission transition was detected. This observation formed the basis for DNA methyltransferase (MTase) activity detection. When the 3′-OH terminus of a duplex DNA was removed, the DNA strands could not be elongated by terminal deoxynucleotidyl transferase (TdT), and little restoration of compound 1 monomer emission was detected. However, in the presence of MTase and endonuclease, the DNA could be specifically methylated and then cleaved into single-stranded fragments. The DNA fragments contained newly generated 3′-OH termini, which could be elongated by TdT. An excimer–monomer transition signal could then be detected. Simple, sensitive, selective, and inexpensive sensing of DNA methylation was therefore established.
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