MICROCHIMICA ACTA
·
2014
·Vol. 182
·期 3
·679-685
·
IF 3.719
Xu Guiyun,Wang Wenting,Li Beibei,Luo Zhonglin,Luo Xiliang
An electrochemical dopamine sensor was developed by electrochemical modification of a carbon paste electrode with a biocomposite made from poly(3,4-ethylenedioxythiophene) (PEDOT) that was doped with double stranded or single stranded DNA. The resulting conducting biocomposite displays excellent electrocatalytic activity towards the oxidation of dopamine (DA) which is attributed to the presence of the DNA dopant. Under optimum conditions and at a working potential of 300 mV, the modified electrode is capable of detecting DA in the 0.25 to 66 μM concentration range. The detection limit is 74 nM. The sensor is not interfered by uric acid and ascorbic acid.
PEDOT biocomposites doped with dsDNA (left) and ssDNA (right) can be electrochemically prepared and used for the sensitive and selective detection of dopamine owing to their excellent catalytic activity towards dopamine oxidation.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2014
·
IF 2.871
Xiaoqian Ouyang,Liqiang Luo,Yaping Ding,Bingdi Liu,Duo Xu
A simple and reliable method for simultaneous determination of purine and pyrimidine (guanine, adenine, thymine and cytosine) was developed at poly(3,4-ethylenedioxythiophene)/electro-deposited graphene modified glassy carbon electrode (PEDOT/GR/GCE). Scanning electron microscopy and electrochemical impedance spectroscopy were used to examine the morphology and interface property of PEDOT/GR film. Differential pulse voltammetry was utilized to investigate the electrochemical behavior of DNA bases in 0.1 M PBS (pH 7.4). The results showed that the peaks of four bases were well separated. The proposed sensor exhibited low detection limit, high sensitivity and wide linear range for simultaneous detection of four DNA bases, with high stability.
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CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS
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2015
·
IF 2.321
Jing-Jing Kong,Zeng-Ping Chen,Yao Chen,Xiu-Fang Yan,Ru-Qin Yu
Accurate quantification of genomic DNA is fundamental to many molecular analyses such as diagnostic assays and genotyping. Due to relatively low and varying extraction rates of DNA from cell lysates by genomic DNA extraction kits, it is desired to quantitatively determine DNA contents directly in cell lysates. However, the coexistence of scatterers (e.g., cell debris), absorbers, and intrinsic fluorophores in cell lysates prevents either UV–Vis spectrophotometric methods or fluorometric methods based on fluorescent dyes and ratiometric models to be directly applied to cell lysates. In this contribution, a novel fluorometric method based on an advanced chemometric model which can effectively eliminate the effects of scatterers and absorbers on fluorescence spectra of cell lysates was proposed for the direct quantification of DNA in lysates of CEM cells. Without cumbersome prior DNA extraction, the proposed method achieved quite stable and accurate DNA quantification with recovery rates in the range of 89%–115%, considerably better than that of either the fluorometric method based on the ratiometric model or the UV–Vis spectrophotometric method coupled with DNA extraction. The proposed method has the advantages of rapidness, simplicity, and high precision, and can be developed into a promising alternative for accurate quantification of genomic DNA.
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TALANTA
·
2014
·
IF 3.511
Xiaofeng Wang,Zheng You,Hailiang Sha,Yong Cheng,Huanhuan Zhu,Wei Sun
A DNA and graphene (GR) bi-layer modified carbon ionic liquid electrode (CILE) was fabricated by an electrodeposition method. GR nanosheets were electrodeposited on the surface of CILE at the potential of −1.3 V and then DNA was further deposited at the potential of +0.5 V on GR modified CILE. Electrochemical performances of the fabricated DNA/GR/CILE were carefully investigated. Then electrochemical behaviors of dopamine (DA) on the modified electrode were studied with the calculated electrochemical parameters. Under the optimized conditions, a linear relationship between the oxidation peak current and the concentration of DA was obtained in the range from 0.1 μmol/L to 1.0 mmol/L with a detection limit of 0.027 μmol/L (3 σ ). The modified electrode exhibited excellent reproducibility, repeatability, stability, validation and robustness for the electrochemical detection of DA. The proposed method was further applied to the DA injection solution and human urine samples determination with satisfactory results.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2013
·
IF 2.906
Ting Wu,Xixi Zang,Mengying He,Siyi Pan,Xiaoyun Xu
Flavonoids are potential sources of natural preservatives. The inhibitory activities of three polymethoxylated flavones (PMFs), three flavones, and four flavonols against Escherichia coli were determined using the microbroth dilution method. Flavonoid inhibitory activities against DNA gyrase from E. coli were estimated by DNA supercoiling. Kaempferol exhibited the greatest antibacterial activity [minimal inhibitory concentration (MIC) = 25 μg/mL], while nobiletin showed the lowest activity (MIC = 177 μg/mL). A good correlation was found between the pIC50 values and the corresponding pMIC values for the purified DNA gyrase (r = 0.9582). The structure–activity relationship analysis suggests that, for a good inhibitory effect, the hydroxyl group substitution at C-5 in the A ring and C-4′ in the B ring and the methoxyl group substitution at C-3 and C-8 in the A ring are essential. The presence of the hydroxyl group at C-6 in the A ring, C-3′ and C-5′ in the B ring, and C-3 in the C ring and the methoxyl group at C-3′ in the B ring greatly reduced inhibition of bacteria. These findings provide a theoretical basis for the development of high-bioactive and low-toxicity natural preservatives.
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ANALYTICAL CHEMISTRY
·
2015
·
IF 5.636
Chunxiang Li,Hongyang Wang,Jing Shen,Bo Tang
Photoactive material is the most crucial factor which intimately determines analytical performances of the photoelectrochemical sensor. On the basis of the high affinity of dipyrido [3,2-a:2′,3′-c] phenazine (dppz) with DNA helix, a novel photoactive intercalator, [(ppy)2Ir(dppz)]+PF6–(ppy = 2-phenylpyridine and dppz = dipyrido [3,2-a:2′,3′-c] phenazine) was prepared and characterized by UV–vis absorption spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. The photoelectrochemical properties of the as-prepared iridium(III) complex immobilized on the ITO electrode was investigated. Either cathodic or anodic photocurrent generation can be observed when triethanolamine (TEOA) or dissolved O2 is used as a sacrificial electron donor/acceptor, respectively. The probable photocurrent-generation mechanisms are speculated. A highly sensitive iridium(III) complex-based photoelectrochemical sensor was proposed for DNA detection via hybridization chain reaction (HCR) signal amplification. Under optimal conditions, the biosensor was found to be linearly proportional to the logarithm of target DNA concentration in the range from 0.025 to 100 pmol L–1 with a detection limit of 9.0 fmol L–1 (3σ). Moreover, the proposed sensor displayed high selectivity and good reproducibility, demonstrating efficient and stable photoelectric conversion ability of the Ir(III) complex.
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ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Yunlei Zhou,Zhiqing Yang,Xue Li,Yue Wang,Huanshun Yin,Shiyun Ai
DNA hydroxymethylation (5-hydroxymethylcytosine, 5hmC) is a kind of new epigenetic modification, which plays key roles in nuclear reprogramming, regulates the gene activity, and initiates the DNA demethylation in mammals. For further understanding the functions of 5hmC and the correlation with tumour, it is essential to develop sensitive and selective methods for detecting and sequencing 5hmC. Herein, a kind of electrochemical biosensor was fabricated for 5hmC detection based on the glycosylation modification of 5hmC and enzymatic signal amplification. Under the catalytic effect of T4 β-glucosyltransferase, the 5hmC in target DNA was chemically modified with glucose. Then with the bridge connection of 1,4-phenyldiboronic acid, alkaline phosphatase was further captured on the electrode surface to catalyze the hydrolysis of p -nitrophenyl phosphate disodium salt to produce p -nitrophenol. Based on the relationship between the electrochemical oxidation signal of p -nitrophenol and the concentration of target DNA, the 5hmC level can be detected with high sensitivity and selectivity. The developed method also showed excellent reproducibility and stability.
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RSC Advances
·
2016
·Vol. 6
·期 10
·7765-7771
·
IF 3.289
Ruipeng Hou,Xiaoqing Niu,Fengling Cui
A highly sensitive and selective label-free biosensor was designed for DNA determination based on target-induced opening of the hairpin DNA and forming a G-quadruplex with protoporphyrin IX (PPIX) as a signal reporter. In the absence of target-DNA (T-DNA), the probe-DNA (P-DNA) forms a hairpin structure. A G-rich sequence in the strand is partially caged in the stem-loop structure and cannot fold into a G-quadruplex. In the presence of T-DNA, the specific combination of targets with the sensing sequence (loop sequence) triggers the release of the G-rich sequence and allows it to fold properly and bind with PPIX resulting in the fluorescence of the G-quadruplex–PPIX providing the readout signal for the sensing event (detection limit of 3.5 nM). Based on the higher efficiency of Pb2+ at stabilizing G-quadruplexes than K+ and the Pb2+-stabilized G-quadruplexes not binding to PPIX, which resulted in fluorescence decrease, the proposed DNA-sensing system can be further exploited as a Pb2+-sensing method. The detection limit for Pb2+ is 2.6 nM.
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NEW JOURNAL OF CHEMISTRY
·
2014
·Vol. 38
·期 9
·4600-4606
·
IF 3.159
Qing Zhang,Yihan Huang,Liju Guo,Cui Chen,Dongmei Guo,Ya Chen,Yingzi Fu
A novel chiral sensing platform, employing a biomolecule-based nanocomposite prepared by calf thymus double stranded DNA, methylene blue and multiwall carbon nanotubes (DNA–MB–MWNTs), was utilized for the discrimination of quinine (QN) and quinidine (QD). The DNA-based nanocomposite, which could be used as an electrochemical sensing unit and chiral probe, was characterized by transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis) and cyclic voltammetry (CV). After the proposed sensing platform interacted with QN and QD, a larger electrochemical signal was obtained from QD. The comparative experiments indicated that the proposed strategy not only simplified the fabrication processes but also enhanced the enantioselective interaction in chiral analysis. In addition, experimental factors such as acidity, interaction time and the concentration of enantiomers were investigated in regards to the effect on enantioselective interaction.
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ANALYTICAL CHEMISTRY
·
2014
·
IF 5.825
Jiaoyun Xia,Meihua Lin,Xiaolei Zuo,Shao Su,Lianhui Wang,Wei Huang,Chunhai Fan,Qing Huang
Contamination of heavy metal ions in an aquatic environment poses a serious threat to human health. More seriously, heavy metal ions are usually present in the environment in a mixture, and the synergetic toxicity of multiple heavy metal ions is revealed (Aragay et al. Chem. Rev. 2011, 111, 3433; Chu et al. Aquat. Toxicol. 2002, 61, 53). Unfortunately, most of the existing methods based on DNA sequences are focusing on the detection of one type of metal ions. Simple and multiplexed detection of multiple metal ions has been poorly investigated and remains challenging. Here, we re-engineered the DNA sequences for Pb2+, Hg2+, and Ag+, through which the binding of multiple metal ions initiated the self-assembly of these DNA sequences. On the basis of our rationally designed multicolor fluorescent labeling of the DNA sequences, cascade fluorescence resonance energy transfer (FRET) occurred. As a result, a fingerprint fluorescent spectrum was produced to indicate the presence of a single type of metal ions or multiple metal ions. The major advantages of our cascade FRET fingerprint technology include the following: (1) the “mix and read” detection mode in homogeneous solution is simple without the need of complicated instruments; (2) only single excitation is required to provide the cascade FRET fingerprint spectrum; (3) multiplexed detection capability can be realized intuitively and sensitively.
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Marine Drugs
·
2017
·Vol. 15
·期 7
·217
·
IF 3.503
Lan-Ting Xin,Lu Liu,Chang-Lun Shao,Ri-Lei Yu,Fang-Ling Chen,Shi-Jun Yue,Mei Wang,Zhong-Long Guo,Ya-Chu Fan,Hua-Shi Guan,Chang-Yun Wang
Currently, DNA topoisomerase I (Topo I) inhibitors constitute a family of antitumor agents with demonstrated clinical effects on human malignancies. However, the clinical uses of these agents have been greatly limited due to their severe toxic effects. Therefore, it is urgent to find and develop novel low toxic Topo I inhibitors. In recent years, during our ongoing research on natural antitumor products, a collection of low cytotoxic or non-cytotoxic compounds with various structures were identified from marine invertebrates, plants, and their symbiotic microorganisms. In the present study, new Topo I inhibitors were discovered from low cytotoxic and non-cytotoxic natural products by virtual screening with docking simulations in combination with bioassay test. In total, eight potent Topo I inhibitors were found from 138 low cytotoxic or non-cytotoxic compounds from coral-derived fungi and plants. All of these Topo I inhibitors demonstrated activities against Topo I-mediated relaxation of supercoiled DNA at the concentrations of 5–100 µM. Notably, the flavonoids showed higher Topo I inhibitory activities than other compounds. These newly discovered Topo I inhibitors exhibited structurally diverse and could be considered as a good starting point for the development of new antitumor lead compounds.Keywords:virtual screening;molecular docking;Topo I inhibitor;low toxic;natural product
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COLLOIDS AND SURFACES B-BIOINTERFACES
·
2016
·
IF 3.902
Yalong Bai,Yan Cui,George C. Paoli,Chunlei Shi,Dapeng Wang,Min Zhou,Lida Zhang,Xianming Shi
Magnetic separation has great advantages over traditional bio-separation methods and has become popular in the development of methods for the detection of bacterial pathogens, viruses, and transgenic crops. Functionalization of magnetic nanoparticles is a key factor for efficient capture of the target analytes. In this paper, we report the synthesis of amino-rich silica-coated magnetic nanoparticles using a one-pot method. This type of magnetic nanoparticle has a rough surface and a higher density of amino groups than the nanoparticles prepared by a post-modification method. Furthermore, the results of hydrochloric acid treatment indicated that the magnetic nanoparticles were stably coated. The developed amino-rich silica-coated magnetic nanoparticles were used to directly adsorb DNA. After magnetic separation and blocking, the magnetic nanoparticles and DNA complexes were used directly for the polymerase chain reaction (PCR), without onerous and time-consuming purification and elution steps. The results of real-time quantitative PCR showed that the nanoparticles with higher amino group density resulted in improved DNA capture efficiency. The results suggest that amino-rich silica-coated magnetic nanoparticles are of great potential for efficient bio-separation of DNA prior to detection by PCR.
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