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https://www.readbyqxmd.com/read/28738657/a-new-strategy-for-fabrication-of-water-dispersible-and-biodegradable-fluorescent-organic-nanoparticles-with-aie-and-esipt-characteristics-and-their-utilization-for-bioimaging
#1
Dazhuang Xu, Meiying Liu, Hui Zou, Jianwen Tian, Hongye Huang, Qing Wan, Yanfeng Dai, Yuanqing Wen, Xiaoyong Zhang, Yen Wei
Fluorescence probes play a crucial role in optical imaging for visualization of complex biological processes. As compared with conventional organic fluorogens, the probes with aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) characteristics show significant advantages in high quantum yield at concentrated and aggregated state, large Stokes shift and low cytotoxicity. However, the synthesis of AIE-active fluorescent probes through the ESIPT mechanism has received only very limited attention...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738656/an-ultrasensitive-fluorescent-nanosensor-for-trypsin-based-on-upconversion-nanoparticles
#2
Mingmin Wu, Xiaoyong Wang, Kun Wang, Zijian Guo
Trypsin and its inhibitors are relevant to many physiological processes and diseases. In this study, a nanosensor capable of detecting trypsin and its inhibitors was designed based on the fluorescence resonance energy transfer (FRET) between upconversion nanoparticle (UCNP) and gold nanoparticle (AuNP). UCNP and AuNP were linked by a trypsin-sensitive peptide DDDDARC, forming the non-fluorescent UCNP-peptide-AuNP nanosensor. In the presence of trypsin, the peptide was cleaved and the quenched fluorescence was restored; in the presence of trypsin inhibitors, the recovery of the fluorescence was decreased...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738645/competitive-fluorescence-anisotropy-polarization-assay-for-atp-using-aptamer-as-affinity-ligand-and-dye-labeled-atp-as-fluorescence-tracer
#3
Yapiao Li, Linlin Sun, Qiang Zhao
We developed an aptamer-based competitive fluorescence anisotropy (FA)/fluorescence polarization (FP) assay for adenosine triphosphate (ATP). Different from the traditional fluorescence polarization immunoassays for small molecules, here DNA aptamer against ATP was used as affinity ligand, and tetramethylrhodamine (TMR) labeled ATP served as fluorescent tracer. The binding between TMR-labeled ATP and aptamer gave large FA due to molecular volume increase and restricted rotation of the dye-labeled ATP. When ATP was added in solution, ATP competitively displaced the TMR-labeled ATP from aptamer affinity complex, causing decrease of FA of TMR-labeled ATP...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738642/terminal-protection-mediated-autocatalytic-cascade-amplification-coupled-with-graphene-oxide-fluorescence-switch-for-sensitive-and-rapid-detection-of-folate-receptor
#4
Rui Wang, Xiaowen Xu, Pei Li, Yan Wang, Wei Jiang
Folate receptor (FR) is over-expressed in most human tumors and has been regarded as biomarker and therapeutic target. Specific and sensitive detection of FR is essential for tumor treatment and drug development. Here, a specific, sensitive and rapid FR detection strategy was proposed based on terminal protection-mediated autocatalytic cascade amplification coupled with graphene oxide fluorescence switch. Firstly, the specific binding of FR to the folate terminally-labeled on a primary trigger DNA (PT-DNA) could protect the PT-DNA from exonuclease I degradation, converting FR detection to PT-DNA detection...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738641/an-interference-free-and-label-free-sandwich-type-magnetic-silicon-microsphere-rgo-based-probe-for-fluorescence-detection-of-microrna
#5
Shiyu Li, Kui He, Rong Liao, Chunyan Chen, Xiaoming Chen, Changqun Cai
An interference-free and label-free sensing platform was developed for the highly sensitive detection of microRNA-21 (miRNA-21) in vitro by magnetic silicon microsphere (MNP)-reduced graphene oxide (rGO)-based sandwich probe. In this method, DNA capture probes (P1) were connected with MNPs at the 5' end and hybridized with completely complementary target miRNA. Subsequently, rGO was retained and induced the fluorescence quenching in the supernatant. Through the magnetic separation, the supernatant environment was simplified and the interference to analytical signal was eliminated...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738627/a-novel-ph-probe-based-on-ratiometric-fluorescent-properties-of-dicyanomethylene-4h-chromene-platform
#6
Xiaolei Liu, Jixun Han, Yan Zhang, Xiaofeng Yang, Yu Cui, Guoxin Sun
We report here a ratiometric pH probe (Z)-2-(2-(2-(4-hydroxyphenyl)-2-(pyrrolidin-1-yl)vinyl) -4H-chromen-4-ylidene)-malononitrile over the pH range of 2.44-6.00. It was synthesized by Knoevenagel Reaction from dicyanomethylene-4H-chromene and pyrrolidine. This is the first example of pyrrolidine as a part of the product structure in Knoevenagel condensation. High selectivity and sensitivity for pH variation were observed with significant fluorescent ratiometric responses and a remarkable Stokes shift (about 138nm)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738624/multiplexed-analysis-combining-distinctly-sized-cdte-mpa-quantum-dots-and-chemometrics-for-multiple-mutually-interfering-analyte-determination
#7
Dayana B Bittar, David S M Ribeiro, Ricardo N M J Páscoa, José X Soares, S Sofia M Rodrigues, Rafael C Castro, Leonardo Pezza, Helena R Pezza, João L M Santos
Semiconductor quantum dots (QDs) have demonstrated a great potential as fluorescent probes for heavy metals monitoring. However, their great reactivity, whose tunability could be difficult to attain, could impair selectivity yielding analytical results with poor accuracy. In this work, the combination in the same analysis of multiple QDs, each with a particular ability to interact with the analyte, assured a multi-point detection that was not only exploited for a more precise analyte discrimination but also for the simultaneous discrimination of multiple mutually interfering species, in the same sample...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738610/a-novel-donor-%C3%AF-acceptor-type-fluorescence-probe-for-sensing-ph-mechanism-and-application-in-vivo
#8
Jianbin Chao, Huijuan Wang, Yongbin Zhang, Caixia Yin, Fangjun Huo, Kailun Song, Zhiqing Li, Ting Zhang, Yaqin Zhao
A novel pH fluorescent probe 1-(pyren-1-yl)-3-(6-methoxypridin-3-yl)-acrylketone, (PMPA), which had a pyrene structure attached to methoxypyridine, was synthesized for monitoring extremely acidic and alkaline pH. The pH titrations indicated that PMPA displayed a remarkable emission enhancement with a pKa of 2.70 and responded linearly to minor pH fluctuations within the extremely acidic range of 1.26-3.97. Interestingly, PMPA also exhibited strong pH-dependent characteristics with pKa 9.32 and linear response to extreme-alkalinity range of 8...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738609/pyridine-ring-containing-twisttetraazaacene-synthesis-physical-properties-crystal-structure-and-picric-acid-sensing
#9
Xianglin Yu, Jiaqi Wan, Shao Chen, Miao Li, Junkuo Gao, Li Yang, Huisheng Wang, Dugang Chen, Zhiquan Pan, Junbo Li
Novel pyridine-ring containing twisttetraazaacene 9,14-diphenylpyreno[4,5-g]isoquinoline (1) and its full-carbon derivative 9,14-diphenyldibenzo[de,qr]tetracene (2) have been synthesized and fully characterized. Studies showed that compound 1 could identify picric acid (PA) over other common nitro compounds with high selectivity and sensitivity. Upon the addition of PA, the emission peak of compound 1 in CH3CN was red shifted from 447 to 555nm with a fluorescence quenching efficiency as high as 95%, the detection limit was calculated to be 2...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738606/a-label-free-fluorometric-assay-for-actin-detection-based-on-enzyme-responsive-dna-templated-copper-nanoparticles
#10
Quanwei Song, Lixia Yang, Hongkun Chen, Rong Zhang, Na Na, Jin Ouyang
Herein, we develop a fluorescent strategy for label-free detection of actin by the in situ formation of double-stranded DNA (dsDNA) templated copper nanoparticles (CuNPs) and the digestion capability of deoxyribonuclease I (DNase I). In this design, the introduction of actin can effectively hinder the enzymic digestion owing to the exceptional target-mediated conformational structure between actin and DNase I. Consequently, the remaining adenine-thymine-rich dsDNA can act as an efficient template for fluorescent CuNPs (λex = 340nm, λem = 585nm) with a Mega-Stokes shifting (245nm)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738605/rapid-one-pot-synthesis-of-mmta-protected-fluorescent-gold-nanoclusters-for-selective-and-sensitive-detection-of-ferric-ion
#11
Jingjing Jiang, Pengfei Gao, Yan Zhang, Guomei Zhang, Ying Zhou, Chuan Dong, Shaomin Shuang
Herein, we demonstrate a straightforward synthesis of fluorescent gold nanoclusters (AuNCs), employing 2-Mercapto-4-methyl-5-thiazoleacetic acid (MMTA) as a reducing and protecting agent by a rapid one-pot synthesis method with a short time of 20min. The as-synthesized MMTA-AuNCs exhibited bright blue emission with a strong peak centered at 430nm and the quantum yield (QY) was evaluated to be 4.0%. Based on the fluorescence quenching mechanism of a surface chelating reaction between MMTA and ferric ion (Fe(3+)), the MMTA-AuNCs were exploited as a fluorescence sensor for sensitive and selective detection of Fe(3+)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738597/sensitive-detection-of-sulfide-based-on-the-self-assembly-of-fluorescent-silver-nanoclusters-on-the-surface-of-silica-nanospheres
#12
Yehan Yan, Kui Zhang, Huan Yu, Houjuan Zhu, Mingtai Sun, Tasawar Hayat, Ahmed Alsaedi, Suhua Wang
Hydrogen sulfide is a toxic and flammable gaseous pollutant often emitted to air as a by-product of water supply, chemical, petroleum and coal industries. It can be transferred into sulfur dioxide in the air under some meteorologic conditions. Herein, we report a novel ratiometric fluorescence method for hydrogen sulfide based on silver nanoclusters and quantum dots. The silver nanoclusters have been self-assemblied onto the surface of silica spheres, which are embedded with red fluorescent quantum dots, to form a dual-emissive nanohybrid...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738593/boron-nitride-nanosheets-as-a-platform-for-fluorescence-sensing
#13
Yuanjin Zhan, Jingjing Yan, Mei Wu, Longhua Guo, Zhenyu Lin, Bin Qiu, Guonan Chen, Kwok-Yin Wong
Hexagonal boron nitride nanosheets (BNNS), one kind of inorganic graphene analogue, exhibit high fluorescence quenching ability via the photo-induced electron transfer (PET) and different affinity toward single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). As a proof of concept, the BNNS was first used as a sensing platform for the rapid detection of DNA and small molecules with high sensitivity and selectivity in this study. This strategy is versatile and quick fluorescence sensing of DNA and extensive DNA related analytes such as metal cations and small molecules...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738592/a-unique-red-emitting-two-photon-fluorescent-probe-with-tumor-specificity-for-imaging-in-living-cells-and-tissues
#14
Xiuqi Kong, Baoli Dong, Nan Zhang, Chao Wang, Xuezhen Song, Weiying Lin
Tumor-specific imaging can provide an attractive approach for the early detection and prognosis of cancer, as well as the precise image-guided tumor-removal surgery. Herein, we describe a unique red-emitting two-photon fluorescent probe (N-BN) for tumor-specific imaging. N-BN utilized Nile Red as the red-emitting two-photon fluorophore and employed biotin as the tumor-specific ligand. In the presence of a variety of biomolecules or in different pH buffers, the fluorescence intensity of N-BN at 655nm showed no noticeable change...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738589/2-aminopurine-probe-in-combination-with-catalyzed-hairpin-assembly-signal-amplification-for-simple-and-sensitive-detection-of-microrna
#15
Chan Liu, Sifang Lv, Hang Gong, Chunyan Chen, Xiaoming Chen, Changqun Cai
A quencher-free and enzyme-free fluorescent sensor was proposed to simply and sensitively detect miRNA via the target catalyzed hairpin assembly (CHA) signal amplification in combination with 2-aminopurine (2-AP) molecular beacon (MBs). This sensor contains two DNA hairpins termed as H1 and H2. H1 labeled by 2-AP needs no quenchers because 2-AP can be quenched through its stacking interaction with the adjacent bases. H2 is partially complementary to H1. In the presence of the target microRNA (miRNA), H1 is unfolded and produces the DNA/RNA complexes, enhancing the fluorescent signal...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738581/the-g-bhq-synergistic-effect-improved-double-quenching-molecular-beacons-based-on-guanine-and-black-hole-quencher-for-sensitive-simultaneous-detection-of-two-dnas
#16
Dongshan Xiang, Fengquan Li, Chenyi Wu, Boan Shi, Kun Zhai
We designed two double quenching molecular beacons (MBs) with simple structure based on guanine (G base) and Black Hole Quencher (BHQ), and developed a new analytical method for sensitive simultaneous detection of two DNAs by synchronous fluorescence analysis. In this analytical method, carboxyl fluorescein (FAM) and tetramethyl-6-carboxyrhodamine (TAMRA) were respectively selected as fluorophore of two MBs, Black Hole Quencher 1 (BHQ-1) and Black Hole Quencher 2 (BHQ-2) were respectively selected as organic quencher, and three continuous nucleotides with G base were connected to organic quencher (BHQ-1 and BHQ-2)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738578/a-simple-method-for-the-multi-elemental-analysis-of-beer-using-total-reflection-x-ray-fluorescence
#17
Ednilton M Gama, Clésia C Nascentes, Roberta P Matos, Gabrielle de C Rodrigues, Guilherme D Rodrigues
A method of direct analysis for quantification of 15 inorganic elements (P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, Br, As, Rb, Sr and Pb) in beers by Total Reflection X-Ray Fluorescence (TXRF) was developed. The experimental conditions were optimized. Direct analysis was compared with the acid digestion procedure to evaluate the effect matrix and the results were satisfactory. The evaluation of the accuracy and precision was realized by analysis of two certified reference materials of natural and waste water. For the majority of the elements, good agreement was achieved between the certified value and the value measured in the CRM´s...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738577/high-bright-fluorescent-carbon-dot-as-versatile-sensing-platform
#18
Mumei Han, Liping Wang, Siheng Li, Liang Bai, Yunjie Zhou, Yue Sun, Hui Huang, Hao Li, Yang Liu, Zhenhui Kang
The surface functionalization will introduce additional functional groups on carbon dots (CDs) surface and then enrich the properties of CDs. Here, we show the various surface functionalized CDs (-COOH, -OH, -SH, -NH2, etc, named as NS-CDs) were synthesized with fascinating features, including high quantum efficiency (38.9%), long-term stability and good biocompatibility. Notably, it can serve as multifunction fluorescent probe in sensing system, including label-free detections in hydrogen peroxide (H2O2) with a wide linear range (1...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738574/a-highly-selective-and-sensitive-fluorescent-probe-for-hypochlorous-acid-and-its-lysosome-targetable-biological-applications
#19
Chang Liu, Xiaojie Jiao, Song He, Liancheng Zhao, Xianshun Zeng
A novel lysosome-targetable fluorescence probe PT-1 based on a photoinduced electron transfer (PET) mechanism has been designed and synthesized. For comparison, the probe PT-2 without morpholine moiety as a lysosome-directing group was also synthesized and investigated. Probes PT-1 and PT-2 exhibited high selectivity, high sensitivity (with the detection limits down to the 10(-10)M range) and response in real time (within 10s) toward HOCl over other reactive oxygen species (ROS). Both PT-1 and PT-2 were cell permeable and enabled them to be used for monitoring of HOCl in living cells...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738572/sequential-determination-of-nickel-and-cadmium-in-tobacco-molasses-and-refill-solutions-for-e-cigarettes-samples-by-molecular-fluorescence
#20
María Carolina Talio, Magdalena Alesso, Mariano Acosta, Verónica S Wills, Liliana P Fernández
In this work, a new procedure was developed for separation and preconcentration of nickel(II) and cadmium(II) in several and varied tobacco samples. Tobacco samples were selected considering the main products consumed by segments of the population, in particular the age (youth) and lifestyle of the consumer. To guarantee representative samples, a randomized strategy of sampling was used. In the first step, a chemofiltration on nylon membrane is carried out employing eosin (Eo) and carbon nanotubes dispersed in sodium dodecylsulfate (SDS) solution (phosphate buffer pH 7)...
November 1, 2017: Talanta
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