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Molecular beacon

Yuanlin Zhang, Yanlin Lv, Xuefei Wang, Aidong Peng, Kaiquan Zhang, Xiaoke Jie, Jijun Huang, Zhiyuan Tian
A newl type of fluorescent probe capable of detecting sulfur mustard (SM) simultant with concentration of 1.2 μM in solution and 0.5 ppm in gas phase has been developed. Owing to its molecular structure with thiocarbonyl component and two piperidyl moieties integrated into the xanthene molecular skeleton, this probe underwent a highly selective nucleophilic reaction with SM simultant and generated a thiopyronin derivative emitting intensive pink fluorescence. The distinct difference in electronic structure between the probe and thiopyronin derivative caused a marked shift of the absorbance band from 445 nm to 567 nm, which enabled an optimal wavelength propitious to excite the thiopyronin derivative but adverse to the probe...
March 12, 2018: Analytical Chemistry
Lisa Becherer, Mohammed Bakheit, Sieghard Frischmann, Silvina Stinco, Nadine Borst, Roland Zengerle, Felix von Stetten
A variety of real-time detection techniques for LAMP based on the change in fluorescence intensity during DNA amplification enable simultaneous detection of multiple targets. However these techniques depend on fluorogenic probes containing target-specific sequences. That complicates the adaption to different targets leading to time-consuming assay optimization. Here, we present the first universal real-time detection technique for multiplex LAMP. The novel approach allows simple assay design and is easy to implement for various targets...
March 6, 2018: Analytical Chemistry
Nurhidayatul Asma Mohamad, Shuhaimi Mustafa, Nur Fadhilah Khairil Mokhtar, Aly Farag El Sheikha
BACKGROUND: The pharmaceutical industry has boosted the gelatin consumption worldwide. This is supported by the availability of cost-effective gelatin production from porcine by-products. However, cross-contamination in gelatin materials where porcine gelatin was unintentionally included in the other animal sources of gelatin that caused significant concerns about halal authenticity. As known, the real-time PCR has provided highly specific and sensitive animal species detection method in various food products...
March 5, 2018: Journal of the Science of Food and Agriculture
Abdullah Alshehri, Anna Grabowska, Snow Stolnik
Design of an efficient delivery system is a generally recognised bottleneck in translation of siRNA technology into clinic. Despite research efforts, cellular processes that determine efficiency of siRNA silencing achieved by different delivery formulations remain unclear. Here, we investigated the mechanism(s) of cellular internalisation of a model siRNA-loaded liposome system in a correlation to the engagement of delivered siRNA with its target and consequent silencing by adopting siRNA molecular beacon technology...
February 28, 2018: Scientific Reports
Bingyuan Guo, Yingying Sheng, Ke Zhou, Quansheng Liu, Lei Liu, Hai-Chen Wu
A new nanopore sensing strategy based on triplex molecular beacon was developed for the detection of specific DNA or multivalent proteins. The sensor is composed of a triplex-forming molecular beacon and a stem-forming DNA component that is modified with a host-guest complex. Upon target DNA hybridizing with the molecular beacon loop or multivalent proteins binding to the recognition elements on the stem, the DNA probe is released and produces highly characteristic current signals when translocated through α-hemolysin...
February 28, 2018: Angewandte Chemie
Huo Xu, Yifan Jiang, Dengyou Liu, Kai Liu, Yafeng Zhang, Suhong Yu, Zhifa Shen, Zai-Sheng Wu
The sensitive detection of cancer-related genes is of great significance for early diagnosis and treatment of human cancers, and previous isothermal amplification sensing systems were often based on the reuse of target DNA, the amplification of enzymatic products and the accumulation of reporting probes. However, no reporting probes are able to be transformed into target species and in turn initiate the signal of other probes. Herein we reported a simple, isothermal and highly sensitive homogeneous assay system for tumor suppressor p53 gene detection based on a new autonomous DNA machine, where the signaling probe, molecular beacon (MB), was able to execute the function similar to target DNA besides providing the common signal...
June 29, 2018: Analytica Chimica Acta
Yi-Jun Shi, Liang-Jun Wang, Yuan-Chin Lee, Chia-Hui Huang, Wan-Ping Hu, Long-Sen Chang
This study presents two sensitive fluorescent assays for sensing heparin on the basis of the electrostatic interaction between heparin and Naja naja atra cardiotoxin 3 (CTX3). Owing to CTX3-induced folded structure of an adenosine-based molecular beacon (MB) or a DNA aptamer against CTX3, a reduction in the fluorescent signal of the aptamer or MB 5'-end labeled with carboxyfluorescein (FAM) and 3'-end labeled with 4-([4-(dimethylamino)phenyl]azo)-benzoic acid (DABCYL) was observed upon the addition of CTX3...
February 19, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Pablo Hernández-Franco, Martín Silva, Rodrigo Franco, Mahara Valverde, Emilio Rojas
Several possible mechanisms have been examined to gain an understanding on the carcinogenic properties of lead, which include among others, mitogenesis, alteration of gene expression, oxidative damage, and inhibition of DNA repair. The aim of the present study was to explore if low concentrations of lead, relevant for human exposure, interfere with Ape1 function, a base excision repair enzyme, and its role in cell transformation in Balb/c-3T3. Lead acetate 5 and 30 μM induced APE1 mRNA and upregulation of protein expression...
February 17, 2018: Environmental Science and Pollution Research International
Shaowei Wang, Xiaochun Wei, Xiaojuan Sun, Chongwei Chen, Jingming Zhou, Ge Zhang, Heng Wu, Baosheng Guo, Lei Wei
Background: Cartilage degeneration affects millions of people but preventing its degeneration is a big challenge. Although RNA interference (RNAi) has been used in human trials via silencing specific genes, the cartilage RNAi has not been possible to date because the cartilage is an avascular and very dense tissue with very low permeability. Purpose: The objective of this study was to develop and validate a novel lipid nanoparticle (LNP)-siRNA delivery system that can prevent cartilage degeneration by knocking down specific genes...
2018: International Journal of Nanomedicine
Mingshu Xiao, Tiantian Man, Changfeng Zhu, Hao Pei, Jiye Shi, Li Li, Xiangmeng Qu, Xizhong Shen, Jiang Li
MicroRNAs (miRNAs) play significant regulatory roles in physiologic and pathologic processes and are considered as important biomarkers for disease diagnostics and therapeutics. Simple, fast, sensitive, and selective detection of miRNAs, however, is challenged by their short length, low abundance, susceptibility to degradation, and homogenous sequence. Here we develop MoS2-loaded molecular beacons (MBs) nanoprobes for highly sensitive and selective detection of miRNAs based on duplex-specific nuclease-mediated signal amplification (DSNMSA)...
February 12, 2018: ACS Applied Materials & Interfaces
Dan Han, Chunying Wei
In this work, we develop a fluorescent molecular beacon based on the DNA-templated silver nanoclusters (DNA-Ag NCs). The skillfully designed molecular beacon can be conveniently used for detection of diverse virulence genes as long as the corresponding recognition sequences are embedded. Importantly, the constructed detection system allows simultaneous detection of multiple nucleic acids, which is attributed to non-overlapping emission spectra of the as-synthesized silver nanoclusters. Based on the target-induced fluorescence enhancement, three infectious disease-related genes HIV, H1N1, and H5N1 are detected, and the corresponding detection limits are 3...
May 1, 2018: Talanta
Shuang Wang, Jian Sun, Jiahui Zhao, Shasha Lu, Xiurong Yang
G-quadruplex has been developed as an innovator for analytical chemistry and biomedicine due to its vibrant binding activity, structural polymorphism and critical roles in biological regulation. Herein, a simple but versatile platform was obtained by integrating split G-quadruplex and fluorophore into a molecular beacon, where the photo-induced electron transfer could occur when the fluorophore approached the preformed G-quadruplex/hemin complexes. Such design subtly combined the G4 disruption-induced fluorescent turn-on strategy and the photo-induced electron transfer property into one platform for constructing the logic circuits...
February 9, 2018: Analytical Chemistry
Zhi-Fa Shen, Feng Li, Yi-Fan Jiang, Chang Chen, Huo Xu, Cong-Cong Li, Zhe Yang, Zai-Sheng Wu
A highly sensitive and selective colorimetric assay based on a multifunctional molecular beacon with palindromic tail (PMB) was proposed for the detection of target p53 gene. The PMB probe can serve as recognition element, primer, and polymerization template and contains a nicking site and a C-rich region complementary to a DNAzyme. In the presence of target DNA, the hairpin of PMB is opened, and the released palindromic tails intermolecularly hybridize with each other, triggering the autonomous polymerization/nicking/displacement cycles...
February 16, 2018: Analytical Chemistry
Wencan Jiang, Suwen Yue, Shang He, Chen Chen, Shanshan Liu, Hong Jiang, Hongli Tong, Xiaoting Liu, Jianan Wang, Fan Zhang, Huizhen Sun, Mianyang Li, Chengbin Wang
Quantitative PCR (qPCR) assay using TaqMan™ probe was widely used in the detection of different nucleic acids. However, this technology has several drawbacks, including false negative results caused by primer-dimer (PD) and false positive issues due to primer-probe aggregations. Here, we designed a modified TaqMan™-Molecular Beacon probe by adding an antisense base and a new type of primer pair named central-homo primer pairs bearing 5-10 bases homologous sequence on the 3' end. Using the HBV qPCR assay as a proof of concept, the new design significantly improved the accuracy of the TaqMan™ qPCR assay for HBV detection...
January 29, 2018: Journal of Virological Methods
Shih-Ying Huang, Jia-Ru Chang, Yu-Chieh Liao, Horng-Yunn Dou, Min-Chieh Chuang
Tuberculosis (TB) remains one of the major infectious diseases worldwide. The pathogenic bacterium, Mycobacterium tuberculosis (M.tb), continuously evolves strains carrying drug-resistance genes, thus posing a growing challenge to TB prevention and treatment. We report a diagnostic system that uses a molecular beacon probe and an assistant strand as the core to simultaneously interact with an M.tb-specific fragment (in IS6110) and a single nucleotide substitution (SNS)-encoded segment (in rpoB) associated with drug resistance...
May 12, 2018: Analytica Chimica Acta
Limin Yang, Bo Liu, Meimei Wang, Jia Li, Wei Pan, Xiaonan Gao, Na Li, Bo Tang
In situ imaging of microRNA (miRNA) in living cells and in vivo is beneficial for promoting the studies on miRNA-related physiological and pathological processes. However, the current strategies usually have low signal-to-background ratio, which greatly affects the sensitivity and imaging performance. To solve this problem, we developed a highly sensitive strategy for fluorescence imaging of miRNA in living cells and in vivo based on graphene oxide (GO) enhanced signal molecules quenching of molecular beacon (MB)...
February 6, 2018: ACS Applied Materials & Interfaces
Hui Zhou, Qian-Jin Han, Zhi-Fang Wu, Hong-Mei Zhong, Jun-Bin Peng, Xun Li, Xiao-Lin Fan
G-triplexes have recently been identified as a new kind of DNA structures. They perhaps possess specific biological and chemical functions similar as identified G-quardruplex, but can be formed by shorter G-rich sequences with only three G-tracts. However, till now, limited G-triplexes sequences have been reported, which might be due to the fact that their stability is one of the biggest concerns during their functional studies and application researches. Herein, we found a G-rich sequence (5'-TGGGTAGGGCGGG-3') which can form a stable G-triplex (Tm ~ 60 °C) at room temperature...
January 30, 2018: Analytical Chemistry
Alexandra L Smith, Dmitry M Kolpashchikov
Hybridization probes have been intensively used for nucleic acid analysis in medicine, forensics and fundamental research. Instantaneous hybridization probes (IHPs) enable signalling immediately after binding to a targeted DNA or RNA sequences without the need to isolate the probe-target complex (e. g. by gel electrophoresis). The two most common strategies for IHP design are conformational switches and split approach. A conformational switch changes its conformation and produces signal upon hybridization to a target...
July 3, 2017: ChemistrySelect
Aurélie Stallivieri, Ludovic Colombeau, Jérôme Devy, Nicolas Etique, Carine Chaintreuil, Bauyrzhan Myrzakhmetov, Mathilde Achard, Francis Baros, Philippe Arnoux, Régis Vanderesse, Céline Frochot
Further improvements in Photodynamic therapy (PDT) necessitate that the dye targets more selectively tumour tissues or neovascularization than healthy cells. Different enzymes such as matrix metalloproteinases (MMPs) are overexpressed in tumour areas. Among these MMPs, gelatinases (MMP-2 and MMP-9) and its activator MMP-14 are known to play a key role in tumour angiogenesis and the growth of many cancers such as glioblastoma multiforme (GBM), an aggressive malignant tumour of the brain. These last years, the concept of photodynamic molecular beacons (PMB) became interesting for controlling the photosensitizer's ability to generate singlet oxygen (1O2) close to target biomolecules as MMPs...
December 24, 2017: Bioorganic & Medicinal Chemistry
Gil Tae Hwang
Sequence-specific detection of nucleic acids has been intensively studied in the field of molecular diagnostics. In particular, the detection and analysis of single-nucleotide polymorphisms (SNPs) is crucial for the identification of disease-causing genes and diagnosis of diseases. Sequence-specific hybridization probes, such as molecular beacons bearing the fluorophore and quencher at both ends of the stem, have been developed to enable DNA mutation detection. Interestingly, DNA mutations can be detected using fluorescently labeled oligonucleotide probes with only one fluorophore...
January 8, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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