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Lin Cheng, BingGuo Wei, Ling Ling He, Ling Mao, Jie Zhang, JinXiang Ceng, DeRong Sun, ChaDan Chen, HanFeng Cui, Nian Hong, Hao Fan
A novel "off-On" electrogenerated chemiluminescence (ECL) biosensor has been developed for the detection of mercury(II) based on molecular recognition technology. The ECL mercury(II) biosensor comprises two main parts: an ECL substrate and an ECL intensity switch. The ECL substrate was made by modifying the complex of Ruthenium(II) tris-(bipyridine)(Ru(bpy)3(2+))/Cyclodextrins-Au nanoparticles(CD-AuNps)/Nafion on the surface of glass carbon electrode (GCE), and the ECL intensity switch is the single hairpin DNA probe designed according to the "molecular recognition" strategy which was functionalized with ferrocene tag at one end and attached to Cyclodextrins (CD) on modified GCE through supramolecular noncovalent interaction...
October 18, 2016: Analytical Biochemistry
Yuhong Liu, Linlin Zhao, Jin Zhang, Jinzha Zhang, Wenbo Zhao, Chun Mao
The work investigates a new fluorescence resonance energy transfer (FRET) system using NaEuF4 nanoparticles (NPs) and Au@Ag2S NPs as the energy donor-acceptor pair for the first time. The NaEuF4/Au@Ag2S NPs-based FRET DNA sensor was constructed with NaEuF4 NPs as the fluorescence (FL) donor and Au@Ag2S core-shell NPs as FL acceptor. In order to find the matching energy acceptor, the amount of AgNO3 and Na2S were controlled in the synthesis process to overlap the absorption spectrum of energy acceptor with the emission spectrum of energy donors...
December 1, 2016: Talanta
Jian-Feng Guo, Dan-Qun Huo, Mei Yang, Chang-Jun Hou, Jun-Jie Li, Huan-Bao Fa, Hui-Bo Luo, Ping Yang
Herein, we have developed a simple, sensitive and paper-based colorimetric sensor for the selective detection of Chromium (Ⅵ) ions (Cr (VI)). Silanization-titanium dioxide modified filter paper (STCP) was used to trap bovine serum albumin capped gold nanoparticles (BSA-Au NPs), leading to the fabrication of BSA-Au NPs decorated membrane (BSA-Au NPs/STCP). The BSA-Au NPs/STCP operated on the principle that BSA-Au NPs anchored on the STCP were gradually etched by Cr (VI) as the leaching process of gold in the presence of hydrobromic acid (HBr) and hence induced a visible color change...
December 1, 2016: Talanta
Zhuang Li, Zhenzhen An, Yongyang Guo, Kangning Zhang, Xiaoling Chen, Dongxia Zhang, Zhonghua Xue, Xibin Zhou, Xiaoquan Lu
In this work, we report a novel Au-Pt bimetallic nanoparticles (Au-PtNPs) decorated on the surface of nitrogen-doped graphene (NG) functionalized with 1, 3, 6, 8-pyrene tetra sulfonic acid sodium salt (PyTS) by direct electrodeposition method. The results of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and electrochemical impendence spectrum (EIS) reveal that the Au-PtNPs were successfully anchored on the surface of NG sheets with a diameter of 20-40nm. Further, the prepared Au-PtNPs/PyTS-NG nanocomposite exhibits superior catalytic activity for the oxidation of nitrite...
December 1, 2016: Talanta
Yan Zhang, Jingjing Jiang, Min Li, Pengfei Gao, Ying Zhou, Guomei Zhang, Shaomin Shuang, Chuan Dong
Herein, a novel, high sensitive, and specific colorimetric sensor for cysteine (Cys) based on pectinase protected gold nanoparticles (P@AuNPs) has been demonstrated for the first time. The P@AuNPs were synthesized by "MW-assisted heat method" and were characterized by UV-vis, TEM, FT-IR and zeta potential techniques. Cys could cause the aggregation of P@AuNPs due to formation of the strong covalent Au-S bond and electrostatic binding. As the Cys concentration increased, the color of the solutions gradually changed from wine-red to blue as well as the large absorption band shifted from 523 to 650nm upon P@AuNPs aggregation...
December 1, 2016: Talanta
Jing Lan, Hong Yan Zou, Qiang Wang, Ping Zeng, Yuan Fang Li, Cheng Zhi Huang
An ultra-sensitive and selective turn off-on fluorescence detection of heparin based on the energy transfer in the BSA-stabilized gold nanoclusters/amino-functionalized graphene oxide (BSA-AuNCs/NH2-GO) hybrids was successfully realized. The BSA-AuNCs containing amounts of carboxyl groups could be absorbed on the surface of NH2-GO through the electrostatic interaction, which resulted in the fluorescence quenching of BSA-AuNCs with high efficiency. However, heparin, possessing high density of negative charge, could compete with BSA-AuNCs to bind NH2-GO and block the energy transfer from BSA-AuNCs to NH2-GO...
December 1, 2016: Talanta
Mei-Sheng Wu, Ruo-Nan Chen, Yao Xiao, Zi-Xin Lv
Here, we propose a simple and novel "signal-on" electrochemiluminescence (ECL) biosensor based on resonance energy transfer (RET) for detection of prostate specific antigen (PSA). The system is composed of Multi-walled carbon nanotubes (MWCNT), polyamidoamine (PAMAM) dendrimer and Au nanoparticles (NPs) film on glassy carbon electrode (GCE) to improve the electron transfer, provide abundant amine group for the immobilization of biomolecules, and amplify the ECL signal. After that, Au nanorods (Au NRs) labeled peptide is modified on electrode surface to serve as ECL-RET acceptor due to the excellent overlap between the ECL emission spectrum of Ru(bpy)3(2+) and the absorption spectrum of Au NRs, leading to the significant decrement of ECL signal...
December 1, 2016: Talanta
Taiping Qing, Xiaoxiao He, Dinggeng He, Zhihe Qing, Kemin Wang, Yanli Lei, Ting Liu, Peng Tang, Yue Li
In this work, we developed a simple, rapid and mild strategy for synthesis of DNA-templated fluorescent gold nanoclusters (AuNCs) through association of gold ions to DNA templates and reduction with 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES). After systematical investigation on the formation of fluorescent AuNCs by using different DNA templates, C5 DNA was found as the best template for the formation of fluorescent AuNCs in this system. This process could be completed within 5min after the reaction beginning under ambient conditions...
December 1, 2016: Talanta
Guangwen Li, Zhijun Li, Xiuhua You, Jinghua Chen, Shurong Tang
A novel label-free electrochemical biosensor for the detection of Hg(2+) based on ligase mediated creation of G-quadruplex-hemin DNAzyme has been developed. Firstly, Cp probe was immobilized on the gold electrode surface through Au-SH bond. In the presence of Hg(2+), Cp and Ap probes were partly hybridized with the LJ probe respectively through the specific T-Hg(2+)-T interaction. Then, the adjacent 3'-OH terminal of Cp will link with the 5'-PO4 terminal of Ap to form a G-rich DNA at the function of T4-ligase...
December 1, 2016: Talanta
Radwan Elzein, Chun-Min Chang, Inna Ponomareva, Wen-Yang Gao, Shengqian Ma, Rudy Schlaf
Metal-organic frameworks (MOFs) deposited from solution have the potential to form 2-dimensional supramolecular thin films suitable for molecular electronic applications. However, the main challenges lie in achieving selective attachment to the substrate surface, and the integration of organic conductive ligands into the MOF structure to achieve conductivity. The presented results demonstrate that photoemission spectroscopy combined with preparation in a system-attached glovebox can be used to characterize the electronic structure of such systems...
October 21, 2016: ACS Applied Materials & Interfaces
Abdul K Parchur, Qifei Li, Anhong Zhou
We report the synthesis, characterization, and application of Prussian blue (PB) functionalized CaMoO4:Eu@SiO2@Au nanorod hybrid nanoparticles (HNPs), with multimodal capabilities such as fluorescence imaging, surface-enhanced Raman spectroscopy (SERS) detection and photothermal therapy (PTT). The average size of CaMoO4:Eu@SiO2 NPs was 206 nm. The HNPs are highly dispersible in water for several weeks without settling and show a strong absorption in the near-infrared region, overlapping with the PB absorption between 600 nm and 1000 nm and the surface plasmon resonance of Au nanorods around 800 nm...
October 21, 2016: Biomaterials Science
Rocío Donamaría, M Concepción Gimeno, Vito Lippolis, José M López-de-Luzuriaga, Miguel Monge, M Elena Olmos
In this paper the reaction products of the basic gold(I) species [Au(C6Cl5)2](-) against the acid salt Ag(OClO3) in the presence of the S-donor macrocyclic ligand 1,4,7-trithiacyclononane ([9]aneS3) are studied in different solvents. Two different isomers of stoichiometry [{Au(C6Cl5)2}Ag([9]aneS3)]2 were isolated depending on the solvent used, dichloromethane or tetrahydrofuran, which show different luminescence in the solid state. X-ray diffraction studies of these compounds reveals that both show the same heteropolynuclear Ag···Au···Au···Ag system but with different Au···Au interaction distances and different relative positions of the cationic fragment [Ag([9]aneS3)](+) in the structure with respect the bimetallic Au···Au core...
October 21, 2016: Inorganic Chemistry
Marcello Marelli, Claudio Evangelisti, Maria Vittoria Diamanti, Vladimiro Dal Santo, Mariapia Pedeferri, Claudia Letizia Bianchi, Luca Schiavi, Alberto Strini
A new protocol to synthesize size-controlled Au nanoparticles (NPs) loaded onto vertically aligned anatase TiO2 nanotubes arrays (TNTAs) prepared by electrochemical anodization is reported. Ligand-free Au NPs (< 10 nm) were deposited onto anatase TNTAs supports, finely tuning the Au loading by controlling the immersion time of the support into metal vapor synthesis (MVS)-derived Au-acetone solutions. The Au/TNTAs composites were characterized by electron microscopies (SEM, (S)TEM), X-ray diffraction, X-ray photoelectron spectroscopy and UV-Vis spectroscopy...
October 21, 2016: ACS Applied Materials & Interfaces
Carlos E Hernandez-Tamargo, Ransel Barzaga, Hans Mikosch, Javier A Martínez, José A Herrera, M H Farías, Mayra P Hernández
The adsorption of sulphur multilayers on Au(100) has been studied using density functional theory (DFT) within the generalized gradient approximation (GGA). The first sulphur layer was adsorbed on the four-fold sites of the unreconstructed Au(100) surface forming a lattice. The experimental parameters of the lattice were reproduced taking into account the surface expansion of the topmost Au(100) layer. This expansion should occur when gold islands are formed after the lifting of hex-reconstruction, which allows the lateral movement of the gold atoms...
October 21, 2016: Physical Chemistry Chemical Physics: PCCP
Alexandre Boulos, Katherine Rand, Josh A Johnson, Jacqueline Gautier, Michael Koster
Infections (including sepsis, meningitis, pneumonia and tetanus) stand as a major contributor to neonatal mortality in Haiti (22%). Infants acquire bacteria that cause neonatal sepsis directly from the mother's blood, skin or vaginal tract either before or during delivery. Nosocomial and environmental pathogens introduce further risk after delivery. The absence of cohesive medical systems and methods for collecting information limits the available data in countries such as Haiti. This study seeks to add more information on the burden of severe bacterial infections and their etiology in neonates of Haiti...
October 19, 2016: Journal of Tropical Pediatrics
K Gopinath, S Kumaraguru, K Bhakyaraj, S Mohan, K S Venkatesh, M Esakkirajan, P R Kaleeswarran, S A Naiyf, S Kadaikunnan, M Govindarajan, G Benelli, A Arumugam
The green fabrication of metal nanoparticles using botanical extracts is gaining increasing research attention in nanotechnology, since it does not require high energy inputs or the production of highly toxic chemical byproducts. Here, silver (Ag), gold (Au) and their bimetallic (Ag/Au) nanoparticles (NPs) were green synthesized using the Gloriosa superba aqueous leaf extract. Metal NPs were studied by spectroscopic (UV-visible spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, XRD and EDX) and microscopic (AFM and TEM) analysis...
October 17, 2016: Microbial Pathogenesis
Liu Yang, Jie Zhang, Faqiong Zhao, Baizhao Zeng
In this work, a novel poly(3,4-ethylenedioxythiophene)@Au nanoparticles (PEDOT@AuNPs) hybrid coating was prepared and characterized. Firstly, the monomer 3,4-ethylenedioxythiophene was self-assembled on AuNPs, and then electropolymerization was performed on a stainless steel wire by cyclic voltammetry. The obtained PEDOT@AuNPs coating was rough and showed cauliflower-like micro-structure with thickness of ∼40μm. It displayed high thermal stability (up to 330°C) and mechanical stability and could be used for at least 160 times of solid phase microextraction (SPME) without decrease of extraction performance...
October 14, 2016: Journal of Chromatography. A
Yohannes Haile-Selassie, Stephanie M Melillo, Timothy M Ryan, Naomi E Levin, Beverly Z Saylor, Alan Deino, Ronald Mundil, Gary Scott, Mulugeta Alene, Luis Gibert
Australopithecus afarensis is the best-known and most dimorphic species in the early hominin fossil record. Here, we present a comparative description of new fossil specimens of Au. afarensis from Nefuraytu, a 3.330-3.207 million-years-old fossil collection area in the Woranso-Mille study area, central Afar, Ethiopia. These specimens include NFR-VP-1/29, one of the most complete mandibles assigned to the species thus far and among the largest mandibles attributed to Au. afarensis, likely representing a male individual...
November 2016: Journal of Human Evolution
Antonino Rapisarda, Nicoletta Giamblanco, Giovanni Marletta
Clinical application of DNA microarrays used for screening of single nucleotide polymorphisms (SNPs) are very important for diagnosis of diseases and appropriate treatment of patients. In this paper localized surface plasmon resonance (LSPR) technique has been used to study the DNA hybridization process for binary solutions of respectively perfectly matching (PM) and single base mismatching (MM) 93-mer ssDNA from KRAS codon 12. 5'-thiol modified 35-mer ssDNA has been linked to the Au nanodisks array as probe with a surface coverage of 2...
October 14, 2016: Journal of Colloid and Interface Science
Deliang Yi, Qian Zhang, Yinghua Liu, Jiaying Song, Yi Tang, Frank Caruso, Yajun Wang
We report the synthesis of chemically asymmetric silica nanobottles (NBs) with a hydrophobic exterior surface (capped with 3-chloropropyl groups) and a hydrophilic interior surface for spatially selective cargo loading, and for application as nanoreactors and nanomotors. The silica NBs, which have a "flask bottle" shape with an average diameter of 350 nm and an opening of ca. 100 nm, are prepared by anisotropic sol-gel growth in a water/n-pentanol emulsion. Due to their chemically asymmetric properties, nanoparticles (NPs) with hydrophilic or hydrophobic surface properties can be selectively loaded inside the NBs or on the outside of the NBs, respectively...
October 20, 2016: Angewandte Chemie
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