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https://www.readbyqxmd.com/read/28738660/novel-biomimetic-enzyme-for-sensitive-detection-of-superoxide-anions
#1
Fang Peng, Tingting Xu, Fan Wu, Chunxue Ma, Yuhong Liu, Jianying Li, Bo Zhao, Chun Mao
Superoxide anion (O2(•-)), one of the most active reactive oxygen species (ROS) in micro-environment of the human body, is involved in some diseases if there is excess O2(•-) associated with oxidative stress. Accurate detection of its concentration has important medical diagnostic significance. In this work, a new electrochemical sensor was designed and fabricated for sensitive detection based on Mn-superoxide dismutase (MnSOD) that decorated onto the surface of magnetic polymeric nanotubes by surface self-assembly processes...
November 1, 2017: Talanta
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
#2
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
#3
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/28738651/recent-advances-in-sample-pre-treatment-for-emerging-methods-in-proteomic-analysis
#4
María Ramos-Payán, Juan A Ocaña-González, Rut M Fernández-Torres, Santiago Maspoch, Miguel Ángel Bello-López
The objective of proteomics is the study of proteins (including their structure elucidation, the characterization of their role in biochemical process, the detection and identification of anomalous modifications in their structures and behavior, etc.) from both a qualitative and quantitative point of view. These studies have to face several difficulties as (a) the intrinsic complexity of protein molecules, (b) the low concentrations of the studied proteins, (c) the complexity of the biological samples (which could lead to interferences from the components of these matrixes), etc...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738650/determination-of-ascorbic-acid-in-serum-samples-by-screen-printed-carbon-electrodes-modified-with-gold-nanoparticles
#5
M Asunción Alonso-Lomillo, Olga Domínguez-Renedo, Abraham Saldaña-Botín, M Julia Arcos-Martínez
This paper shows the ability of simple modified screen-printed devices for the electrochemical detection of ascorbic acid in different samples, including serum samples. Even if the presence of uric acid does not greatly affect the analysis of ascorbic acid using screen-printed carbon electrodes modified by gold nanoparticles, dopamine must be considered an interferent. Thus, the joint determination of the three compounds has been set out using methods of multivariate calibration. The validated models, built by partial least squares regressions, have been used to determine the concentration of ascorbic acid, dopamine and uric acid of spiked serum samples, with successful results...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738649/well-defined-magnetic-surface-imprinted-nanoparticles-for-selective-enrichment-of-2-4-dichlorophenoxyacetic-acid-in-real-samples
#6
Le Sheng, Yulong Jin, Yonghuan He, Yanyan Huang, Liushui Yan, Rui Zhao
Superparamagnetic core-shell molecularly imprinted polymer nanoparticles (MIPs) were prepared via surface initiated reversible-addition fragmentation chain transfer (si-RAFT) polymerization for the selective recognition of 2,4-dichlorophenoxyacetic acid (2,4-D) in real samples. The construction of uniform core-shell structure with a 50nm MIP layer was successfully accomplished, which favored mass transfer and resulted in fast recognition kinetics. The static equilibrium experiments revealed the satisfied adsorption capacity and imprinting efficiency of Fe3O4@MIP...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738647/development-of-an-analytical-methodology-for-obtaining-quantitative-mass-concentrations-from-laap-tof-ms-measurements
#7
Rachel Gemayel, Brice Temime-Roussel, Nathalie Hayeck, Adrien Gandolfo, Stig Hellebust, Sasho Gligorovski, Henri Wortham
Laser ablation aerosol particle-time of flight mass spectrometer (LAAP-ToF-MS) measures the size number of particles, and chemical composition of individual particles in real-time. LAAP-ToF-MS measurements of chemical composition are difficult to quantify, mostly because the instrument sensitivities to various chemical species in the multicomponent atmospheric aerosol particles are unknown. In this study, we investigate a field-based approach for quantitative measurements of ammonium, nitrate, sulfate, OC, and EC, in size-segregated atmospheric aerosols, by LAAP-ToF-MS using concurrent measurements from high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), and multi-angle absorption photometer (MAAP)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738637/sensitive-detection-of-estriol-hormone-in-creek-water-using-a-sensor-platform-based-on-carbon-black-and-silver-nanoparticles
#8
Paulo A Raymundo-Pereira, Anderson M Campos, Fernando C Vicentini, Bruno C Janegitz, Camila D Mendonça, Leonardo N Furini, Naiza V Boas, Marcelo L Calegaro, Carlos J L Constantino, Sergio A S Machado, Osvaldo N Oliveira
We report the electrochemical detection of estriol using carbon black nanoballs (CNB) decorated with silver nanoparticles (AgNP) as electrode material. Homogeneous, porous films on glassy carbon electrodes (GCE) were obtained, with diameters of 20 - 25nm for CNB and 5 - 6nm for AgNP. CNB/AgNP electrodes had increased conductivity and electroactive area in comparison with bare GCE and GCE/CNB, according to cyclic voltammetry and electrochemical impedance spectroscopy. The oxidation potential peak was also down shifted by 93mV, compared to the bare GC electrode...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738630/simultaneous-determination-of-paracetamol-and-ciprofloxacin-in-biological-fluid-samples-using-a-glassy-carbon-electrode-modified-with-graphene-oxide-and-nickel-oxide-nanoparticles
#9
Anderson Martin Santos, Ademar Wong, Adriana Araújo Almeida, Orlando Fatibello-Filho
A simple and highly selective electrochemical method using a glassy carbon electrode (GCE) modified with graphene oxide (GO) and nickel oxide nanoparticles (NiONPs) was developed for the simultaneous determination of paracetamol (PAR) and ciprofloxacin (CIP). The electrochemical characterisation of the modified GCE was performed by cyclic voltammetry and electrochemical impedance spectroscopy. The morphological characterisation of the GO and NiONPs was performed by scanning electron microscopy and transmission electron microscopy...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738620/proteins-in-microbial-synthesis-of-selenium-nanoparticles
#10
Anna V Tugarova, Alexander A Kamnev
Biogenic formation of nano-sized particles composed of various materials (in particular, selenium) by live microorganisms is widespread in nature. This phenomenon has been increasingly attracting the attention of researchers over the last decade not only owing to a range of diverse applications of such nanoparticles (NPs) in nanobiotechnology, but also because of the specificity of methodologies and mechanisms of NPs formation related to "green synthesis". In this mini-review, recent data are discussed on the multifaceted role of proteins in the processes of microbial reduction of selenium oxyanions and the formation of Se NPs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738618/high-sensitivity-surface-plasmon-resonance-biosensor-for-detection-of-microrna-and-small-molecule-based-on-graphene-oxide-gold-nanoparticles-composites
#11
Qing Li, Qing Wang, Xiaohai Yang, Kemin Wang, Hua Zhang, Wenyan Nie
A versatile and sensitive surface plasmon resonance (SPR) biosensor based on two layers of graphene oxide-gold nanoparticles (GO-AuNPs) composites was designed for the detection of microRNA (miRNA) and small molecule adenosine. The bottom layer, which acted as a functionalized substrate on the sensor chip, provided a high specific surface area convenient for the immobilization of capture DNA molecules. The upper layer served as a signal-amplification element. By employing these two layers of GO-AuNPs composites, the dual amplification strategy was achieved so that a measurement of miRNA-141 with a detection limit of 0...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738614/in-situ-synthesis-of-reduced-graphene-oxide-gold-nanoparticles-modified-electrode-for-speciation-analysis-of-copper-in-seawater
#12
Ming Liu, Dawei Pan, Wen Pan, Yun Zhu, Xueping Hu, Haitao Han, Chenchen Wang, Dazhong Shen
In this paper, reduced graphene oxide/gold nanoparticle/Nafion (rGO/AuNP/Nafion) modified electrode was fabricated through in-situ synthesis and used for determination of copper ions in strong salt electrolyte (0.5M NaCl) by differential pulse anodic stripping voltammetry (DPASV). This in-situ synthesis procedure was based on the ion-exchange and electrochemical reduction. The use of rGO provided a larger electrode surface and the presence of more active sites, while electron transfer was accelerated by incorporating AuNPs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738607/novel-colorimetric-assay-for-paraquat-detection-on-silica-bead-using-negatively-charged-silver-nanoparticles
#13
Weena Siangproh, Thachkorn Somboonsuk, Orawan Chailapakul, Kriangsak Songsrirote
A simple, rapid, sensitive, and economical method based on colorimetry for the determination of paraquat, a widely used herbicide, was developed. Citrate-coated silver nanoparticles (AgNPs) were synthesized as the colorimetric probe. The mechanism of the assay is related to the aggregation of negatively charged AgNPs as induced by positively-charged paraquat resulting from coulombic attraction which causes the color to change from a deep greenish yellow to pale yellow in accordance with the concentrations of paraquat...
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
#14
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/28738584/production-of-stable-and-sensitive-sers-substrate-based-on-commercialized-porous-material-of-silanized-support
#15
Han Zhang, Lin Sun, Yuan Zhang, Yan Kang, Huilian Hu, Huirong Tang, Yiping Du
This paper reports accurate synthesis of a new type of surface-enhanced Raman spectroscopy (SERS) substrate based on gold nanoparticles decorated 201 red silanized diatomaceous supports. The developed SERS substrate is easy to fabricate, cost effective and offers sensitive rapid detection. The performance and stability of the SERS substrate was investigated and the results showed good SERS activity of substrate that can last for more than 6 months. Tiazophos and phosmet pesticides in aqueous solutions can be detected clearly at a low concentration of 0...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738579/compositional-engineering-of-vopcpho-tio2-nano-composite-to-reduce-the-absolute-threshold-value-of-humidity-sensors
#16
Mohamad Izzat Azmer, Fakhra Aziz, Zubair Ahmad, Ehsan Raza, Mansoor Ani Najeeb, Noshin Fatima, Tahani M Bawazeer, Mohammad S Alsoufi, R A Shakoor, Khaulah Sulaiman
This research work demonstrates compositional engineering of an organic-inorganic hybrid nano-composites for modifying absolute threshold of humidity sensors. Vanadyl-2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine (VOPcPhO), an organic semiconductor, doped with Titanium-dioxide nanoparticles (TiO2 NPs) has been employed to fabricate humidity sensors. The morphology of the VOPcPhO:TiO2 nano-composite films has been analyzed by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738568/novel-imidazole-fluorescent-poly-ionic-liquid-nanoparticles-for-selective-and-sensitive-determination-of-pyrogallol
#17
Zhouyang Li, Yiwen Yang, Yanbo Zeng, Jianbo Wang, Haiqing Liu, Longhua Guo, Lei Li
This paper reports novel imidazole fluorescent poly(ionic liquid) nanoparticles (FPILNs) of poly(1-[(4-methyphenyl)methyl]-3-vinyl-imidazolium bromide (poly([MVI]Br) for selective and sensitive determination of pyrogallol. An imidazole ionic liquid of 1-[(4-methyphenyl)methyl]-3-vinyl-imidazolium bromide ([MVI]Br) was synthesized and used as the only monomer to obtain poly([MVI]Br) possessing phenyl fluorophores using a radical polymerization technique. The obtained poly([MVI]Br) can form nanoparticles in water...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738561/silver-triangular-nanoplates-as-an-high-efficiently-fret-donor-acceptor-of-upconversion-nanoparticles-for-ultrasensitive-turn-on-off-protamine-and-trypsin-sensor
#18
Hongyu Chen, Aijin Fang, Youyu Zhang, Shouzhuo Yao
Silver triangular nanoplates (STNPs) as a high efficient fluorescence quenching reagent of upconversion nanoparticles (UCNPs) was used to constract a novel label-free fluorescence nanosensor for ultrasensitive detection of protamine and trypsin based on fluorescence resonance energy transfer (FRET) between STNPs and UCNPs. In this assay, the negatively charged STNPs can bind with positively charged UCNPs through electrostatic interaction, and then quenched the fluorescence of UCNPs. When protamine was added to the mixture of UCNPs-STNPs, the STNPs interacted with protamine and then detached from the surface of UCNPs and aggregated, which result in the recovery of the fluorescence of UCNPs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738560/novel-metal-nanoparticle-enhanced-fluorescence-for-determination-of-trace-amounts-of-fluoroquinolone-in-aqueous-solutions
#19
Sheng-Nan Yin, Ting Yao, Tun-Hua Wu, Yong Zhang, Ping Wang
Metal-enhanced fluorescence of fluoroquinolones (FQs) was first observed in aqueous solutions. In addition, a new type of silver nanoparticles (AgNP) was synthesized with simple and easy synthetic processes and environmentally friendly compounds. The effects of different concentrations of AgNPs on the fluorescence behaviours of ciprofloxacin (CIP), enrofloxacin (ENR) and lomefloxacin (LMF) in aqueous solutions were investigated, respectively. The experimental results demonstrated that the fluorescence peak shapes and the locations of the features in the excitation and emission spectra for each FQ that was mixed with AgNPs were almost the same as those of the standard FQs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738519/magnetic-iron-oxide-nanoparticles-as-novel-and-efficient-tools-for-atherosclerosis-diagnosis
#20
REVIEW
María Gabriela Montiel Schneider, Verónica Leticia Lassalle
Cardiovascular complications derivate from atherosclerosis are the main cause of death in western world. An early detection of vulnerable atherosclerotic plaques is primordial for a better care of patients suffering the pathology. In this context nanotechnology has emerged as a promising tool to achieve this goal. Nanoparticles based on magnetic iron oxide (MNPs) have been extensively studied in cardiovascular diseases diagnosis, as well as in the treatment and diagnostic of other pathologies. The present review aims to describe and analyze the most current literature regarding to this topic, offering the level of detail required to reproduce the experimental tasks providing a critical input of the latest available reports...
July 19, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
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