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Falan Li, Yemin Guo, Xiangyou Wang, Xia Sun
A dual-target electrochemical aptasensor was developed for the simultaneous detection of multiple antibiotics based on metal ions as signal tracers and nanocomposites as signal amplification strategy. Metal ions such as Cd2+ and Pb2+ could generate distinct differential pulse voltammetry (DPV) peaks. When targets were present, kanamycin (KAN) and streptomycin (STR) as models, the KAN aptamer (KAP) and STR aptamer (STP) were released from their complementary strands, with more change of Cd2+ and Pb2+ corresponding to peak currents...
April 13, 2018: Biosensors & Bioelectronics
Ryan T Pekarek, Hugo Celio, Michael J Rose
We report the utility of controlled spacing of molecular monolayers on Si(111) surfaces by the use of sterically bulky silanes. The steric bulk of a 3,5-diphenolic linker of type Ph-diO-SiR3 (R = hexyl, phenyl, i Pr)-as well as the smaller Ph-diOMe-is shown to control the surface coverage on Si(111). The para substituent was also changed from -F (small) to -OTf (triflate, large) to modulate the conformation of a selected bulky silane (SiR3 ; R = hexyl) to further control the steric environment of the monolayer...
May 21, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Konrad Rudnicki, Lukasz Poltorak, Sławomira Skrzypek, Ernst J R Sudholter
Short pieces of fused silica capillary tubing were used to support an electrified liquid - liquid interface. A methyl deactivated silica capillary having a diameter of 25 µm was filled with 1,2-dichloroethane solution and served as the organic part of the liquid - liquid interface. A non-deactivated fused silica capillary having a diameter of 5, 10 or 25 µm were filled with an aqueous HCl solution and served as the aqueous part of the electrochemical cell. For the latter, silanization of the capillary interior with chlorotrimethylsilane allowed for a successful phase reversal...
May 21, 2018: Analytical Chemistry
Stefanie Schlicht, Sandra Haschke, Vladimir Mikhailovskii, Alina Manshina, Julien Bachmann
Nanoporous iridium electrodes are prepared and electrochemically investigated towards the water oxidation (oxygen evolution) reaction. The preparation is based on 'anodic' aluminum oxide templates, which provide straight, cylindrical nanopores. Their walls are coated using atomic layer deposition (ALD) with a newly developed reaction which results in a metallic iridium layer. The ALD film growth is quantified by spectroscopic ellipsometry and X-ray reflectometry. The morphology and composition of the electrodes are characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction...
May 2018: ChemElectroChem
Donglei Bu, Yingqi Xiong, Ying Ning Tan, Miao Meng, Paul J Low, Dai-Bin Kuang, Chun Y Liu
Layer-by-layer assembly of the dirhodium complex [Rh2 (O2 CCH3 )4 ] (Rh2 ) with linear N , N '-bidentate ligands pyrazine (LS ) or 1,2-bis(4-pyridyl)ethene (LL ) on a gold substrate has developed two series of redox active molecular wires, (Rh2 LS ) n @Au and (Rh2 LL ) n @Au ( n = 1-6). By controlling the number of assembling cycles, the molecular wires in the two series vary systematically in length, as characterized by UV-vis spectroscopy, cyclic voltammetry and atomic force microscopy. The current-voltage characteristics recorded by conductive probe atomic force microscopy indicate a mechanistic transition for charge transport from voltage-driven to electrical field-driven in wires with n = 4, irrespective of the nature and length of the wires...
April 14, 2018: Chemical Science
Dorota Matyszewska, Ewelina Napora, Kamila Żelechowska, Jan F Biernat, Renata Bilewicz
The synthesis, characterization, and the influence of single-walled carbon nanotubes (SWCNTs) modified with an anticancer drug doxorubicin (DOx) on the properties of model biological membrane as well as the comparison of the two modes of modification has been presented. The drug was covalently attached to the nanotubes either preferentially on the sides or at the ends of the nanotubes by the formation of hydrazone bond. The efficiency of the modification was proved by the results of FTIR, Raman, and thermogravimetric analysis...
2018: Journal of Nanoparticle Research: An Interdisciplinary Forum for Nanoscale Science and Technology
Zeinab Tahmasebi, Saied Saeed Hosseiny Davarani, Ali Akbar Asgharinezhad
In this work, a novel, inexpensive and fast strategy was described for selective and effective extraction and determination of propylthiouracil (PTU) with a high polarity (log P = 1.2) based on electromembrane extraction (EME) followed by differential pulse voltammetry (DPV). For this purpose, copper nanoparticles (CuNPs)-decorated hollow fiber was used as the selective membrane for EME of PTU in urine samples. The influential parameters on extraction such as extraction solvent, pH, agitation speed, applied potential and extraction time were systematically investigated...
May 9, 2018: Biosensors & Bioelectronics
Mohammad Hasanzadeh, Amir Zargami, Hossein Navay Baghban, Ahad Mokhtarzadeh, Nasrin Shadjou, Soltanali Mahboob
The genetic disorder phenylketonuria (PKU) is the inability to metabolize phenylalanine because of a lack of the enzyme phenylalanine hydroxylase. Phenylalanine is used to biochemically form proteins, coded for by DNA. The development of an apta-assay for detection of l-Phenylalanine is presented in this work. A highly specific DNA-aptamer, selected to l-Phenylalanine was immobilized onto a gold nanostructure and electrochemical measurements were performed in a solution containing the phosphate buffer solution with physiological pH...
May 16, 2018: International Journal of Biological Macromolecules
Maria de Fátima Alves, Ricardo Augusto Moreira de Souza Corrêa, Filipe Soares da Cruz, Diego Leoni Franco, Lucas Franco Ferreira
This paper reports the electrosynthesis and characterisation of a polymeric film derived from 2-hydroxybenzamide over a graphite electrode and its application as an enzymatic biosensor for the determination and quantification of the pesticide fenitrothion. The material was analysed by scanning electron microscopy and its electrochemical properties characterised by cyclic voltammetry and electrochemical impedance spectroscopy. The enzyme tyrosinase was immobilised over the modified electrode by the drop and dry technique...
May 16, 2018: Analytical Biochemistry
M Trejo-Valdez, S R Hernández-Guzmán, M E Manriquez-Ramírez, H Sobral, H Martínez-Gutiérrez, C Torres-Torres
Removal of hexavalent chromium was accomplished by using photocatalyst materials of TiO2 doped with tungsten oxide, environmental air as oxygen supply and white light as irradiation source. Dichromate anions in concentration ranges of 50 to 1000 μg/L were removed by means of aqueous dispersions of TiO2 doped with tungsten. The aqueous chromium analyses were performed by Differential Pulse Voltammetry technique. Additionally, mineralization of CO2 gas was promoted by the photocatalysis process, as was clearly shown by Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS) analyses obtained from the TiO2 samples recovered after photocatalytic experiments...
May 15, 2018: Journal of Hazardous Materials
Hakan Törer, Elif Burcu Aydın, Mustafa Kemal Sezgintürk
In this study we designed an ultrasensitive electrochemical immunosensor for RACK 1 detection using 11-cyanoundecyltrimethoxysilane (11-CUTMS) as a immobilization matrix to immobilize biorecognition element. The used silane agent (11-CUTMS) provides a favorable platform for efficient loading of anti-RACK 1 antibody. The effective loading of the biorecognition element on the 11-CUTMS matrix was monitored by scanning electron microscopy (SEM), atomic force microscopy (AFM) images and fourier transform infrared spectroscopy (FTIR) spectra...
September 18, 2018: Analytica Chimica Acta
Lixia Guo, Xiaoju Wang, Liheng Feng
A blue emitter, 3,3'-(2,2'-dimethoxy-[1,1'-binaphthalene]-6,6'-diyl)bis(9-benzyl-9H-carbazole), was synthesized by Suzuki coupling reaction. The photophysical properties of the emitter in solution were firstly investigated by UV-Vis absorption and fluorescence emission techniques. The results indicate that the emitter has excellent optical and electron transfer properties. The maximum absorption and emission peaks of the emitter are 302 nm and 406 nm with 67.4% fluorescence quantum yield in chloroform, respectively...
May 10, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Seyed Alireza Shahamirifard, Mehrorang Ghaedi, Zahra Razmi, Shaaker Hajati
The determination of gallic acid (GA) and uric acid (UA) is essential due to their biological properties. Numerous methods have been reported for the analysis of GA and UA in various real samples. However, the development of a simple, rapid and practical sensor still remains a great challenge. Here, a carbon paste electrode (CPE) was modified by nanocomposite containing zirconia nanoparticles (ZrO2 NPs), Choline chloride (ChCl) and gold nanoparticles (AuNPs) to construct ZrO2 -ChCl-AuNPs/CPE as electrochemical sensor for the simultaneous electro-oxidation of GA and UA...
May 8, 2018: Biosensors & Bioelectronics
Golam Moula, Tsuyoshi Matsumoto, Matthias E Miehlich, Karsten Meyer, Kazuyuki Tatsumi
An unprecedented, super oxidized all-ferric iron-sulfur cubanoid cluster with all terminal thiolates, Fe₄S₄(STbt)₄ (3) [Tbt = 2,4,6-tris{bis(trimethylsilyl)methyl}phenyl], has been isolated from the reaction of the bis-thiolate complex Fe(STbt)₂ (2) with elemental sulfur. This cluster 3 has been characterized by X-ray crystallography, zero-field ⁵⁷Fe Mössbauer spectroscopy, cyclic voltammetry, and other relevant physico-chemical methods. Based on all data, the electronic ground state of the cluster has been assigned to be Stot = 0...
May 18, 2018: Angewandte Chemie
Jason Melidonie, Junzhi Liu, Yubin Fu, Jan J Weigand, Reinhard Berger, Xinliang Feng
One antiaromatic polycyclic hydrocarbon (PH) with and without solubilizing tert-butyl substituents, namely s-indaceno[2,1- a:6,5- a']dipyrene (IDPs), has been synthesized by a four-step protocol. The IDPs represent the longitudinal, peri-extension of the indeno[1,2- b]fluorene skeleton towards a planar 40 π-electron system. Their structures were unambiguously confirmed by X-ray crystallographic analysis. The optoelectronic properties were studied by UV/Vis absorption spectroscopy and cyclic voltammetry. These studies revealed that peri-fusion renders the IDP derivatives with a narrow optical energy gap of 1...
May 18, 2018: Journal of Organic Chemistry
Haitang Yang, Xiaoyu Zhao, Haibo Chang, Ruimin Xing, Jing-He Yang, Shanhu Liu, D Xiuhua Liu
A novel chemically modified electrode was constructed in this study based on the carbon nanotubes-supported Pd nanoparticles (Pd/CNTs). It was demonstrated that the sensor could be used for the determination of dopamine (DA) and paracetamol (PA). The measurements were carried out through application of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometric i-t curve. Under optimum conditions and using the amperometric i-t curve method, the modified electrode provided linear response versus dopamine concentrations in the range of 0...
January 1, 2018: Journal of Nanoscience and Nanotechnology
Jeonghyun Kim, Soo-Jin Park, Seok Kim
We fabricated KOH-activated reduced graphene oxide (rGO)/Fe2O3 composites using a facile twostep synthesis by homogeneous precipitation and subsequent reduction of the GO. The total specific capacity of Fe2O3/KOH-activated rGO was higher than the sum of KOH-activated rGO and nanoparticle Fe2O3. It indicated a synergy effect of rGO, and Fe2O3 on the improvement of electrochemical performance. The structure and morphology of the composites were characterized by Fourier transform infrared spectrometer (FTIR), scanning electron microscopy (SEM)...
January 1, 2018: Journal of Nanoscience and Nanotechnology
Jin-Young Hong, Yongju Jung, Kwang-Man Kim, Seok Kim
Zeolitic imidazolate framework-sulfur composites were synthesized by a simple solvothermal reaction. Furthermore, following thermal treatment enable electrochemical properties to be improved. In order to investigate optimal temperature, we conducted thermal treatment as a function of different temperature. The morphology of the composites was examined by Field Emission Scanning Electron Microscopy and Fourier Transform Infra-red Spectroscopy. Electrochemical characterizations were also conducted by cyclic voltammetry and Galvanostatic charge-discharge tests...
January 1, 2018: Journal of Nanoscience and Nanotechnology
Jin-Seob Park, Yongju Jung, Seok Kim
Graphene nanosheet (GNS)/Molybdenum disulfide (MoS2)-sulfur composites were prepared by an In Situ solution-phase synthesis method. The practical implementation of lithium sulfur battery has not been realized by low discharge capacity and fast capacity decay during cycling owing to dissolution of lithium polysulfide into the electrolyte. In this work, we found that the GNS/MoS2 composites could mitigate the polysulfide dissolution and enhance the cycling stability via the MoS2 interaction. Electrochemical performances of prepared composites were evaluated in lithium batteries by galvanostatic cycling and cyclic voltammetry...
January 1, 2018: Journal of Nanoscience and Nanotechnology
Chao Huang, Yuan Yang, Jijiang Fu, Jiawei Wu, Hao Song, Xuming Zhang, Biao Gao, Paul K Chu, Kaifu Huo
Flexible supercapacitors (SCs) are desirable for elastic and clothing electronic products owning to their considerable safety, high foldability and outstanding power density. Herein, multilayered films composed of alternating mesoporous Nb4N5 nanobelts and rGO nanosheets (Nb4N5/rGO) are designed and fabricated exhibiting good flexibility. The folding Nb4N5/rGO film electrode reveals an areal capacitance of 141 mF cm-2 (at 1 mA cm-2) along with remarkable cycling stability (the capacitance retention is 90% after 6,000 cycles)...
January 1, 2018: Journal of Nanoscience and Nanotechnology
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