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Keith J Stine, Kenise Jefferson, Olga V Shulga
Nanoporous gold (NPG) is a material of emerging interest for immobilization of biomolecules, especially enzymes. The material provides a high surface area form of gold that is suitable for physisorption or for covalent modification by self-assembled monolayers. The material can be used as a high surface area electrode and with immobilized enzymes can be used for amperometric detection schemes. NPG can be prepared in a variety of formats from alloys containing between 20 and 50 % atomic composition of gold and less noble element(s) by dealloying procedures...
2017: Methods in Molecular Biology
Matteo Bonomo, Danilo Dini, Andrea Giacomo Marrani
The adsorption of I(-) and I3(-) anions, i.e. the two species constituting the most common redox couple of dye-sensitized solar cells (DSCs), onto the surface of screen-printed nanoporous NiO was studied by means of X-ray photoelectron spectroscopy (XPS). Mesoporous NiO films were deposited on transparent metallic fluorine-doped tin oxide (FTO) and polarized as working electrodes in a three-electrode cell with differently concentrated I(-)/I3(-) electrolytes to simulate the different conditions experienced by the NiO cathodes during the lifecycle of a p-type DSC (p-DSC) at those atomic sites not passivated by the dye...
October 21, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Abel Santos, Cheryl Suwen Law, Dominique Wong Chin Lei, Taj Pereira, Dusan Losic
In this study, we present an advanced nanofabrication approach to produce gradient-index photonic crystal structures based on nanoporous anodic alumina. An apodization strategy is for the first time applied to a sinusoidal pulse anodisation process in order to engineer the photonic stop band of nanoporous anodic alumina (NAA) in depth. Four apodization functions are explored, including linear positive, linear negative, logarithmic positive and logarithmic negative, with the aim of finely tuning the characteristic photonic stop band of these photonic crystal structures...
October 21, 2016: Nanoscale
Xiaoyang Shi, Hang Xiao, Klaus Lackner, Xi Chen
A great deal of information exists concerning the hydration of ions in bulk water. Much less noticeable, but equally ubiquitous is the hydration of ions holding on to several water molecules in nanoscopic pores or in natural air at low relative humidity. Such hydration of ions with a high ratio of ions to water molecules (up to 1:1) are essential in determining the energetics of many physical and chemical systems. Here we present a quantitative analysis of the energetics of ion hydration in nanopores based on molecular modeling of a series of basic salts associated with different numbers of water molecules...
October 20, 2016: Chemistry: a European Journal
Mordjane Boukhet, Fabien Piguet, Hadjer Ouldali, Manuela Pastoriza-Gallego, Juan Pelta, Abdelghani Oukhaled
The transport of macromolecules through nanopores is involved in many biological functions and is today at the basis of promising technological applications. Nevertheless the interpretation of the dynamics of the macromolecule/nanopore interaction is still misunderstood and under debate. At the nanoscale, inside biomimetic channels under an external applied voltage, electrophoresis, which is the electric force acting on electrically charged molecules, and electroosmotic flow (EOF), which is the fluid transport associated with ions, contribute to the direction and magnitude of the molecular transport...
October 20, 2016: Nanoscale
Hiroshi Yoshida, Yusuke Goto, Rena Akahori, Yasuhiko Tada, Shohei Terada, Motonori Komura, Tomokazu Iyoda
We report a novel approach to slow the translocation of single-stranded DNA (ssDNA) by employing polyethylene oxide (PEO) filled nano-cylindrical domains as transportation channels. DNA strands were demonstrated to electrophoretically translocate through PEO filled cylindrical domains with diameters of 2 and 9 nm, which were self-assembled by amphiphilic liquid crystalline block copolymers. The average translocation rate of ssDNA strands was effectively reduced to an order of 10 μs per nucleotide, which was 1-2 orders slower than that attained by utilizing conventional solid-state nanopore devices...
October 20, 2016: Nanoscale
Richard M Crooks
This article provides a summary of the Faraday Discussion on single entity electrochemistry held in York, U.K., in early September, 2016. The introduction provides some context for thinking about electrochemical studies of single entities. The next four sections follow the themes of the meeting as they relate to single-entity electrochemistry: (1) nanoparticles, nanotubes, and nanowires; (2) nanopores and nanofluidics; (3) complex surfaces and reactions at the nanoscale; and (4) molecular electroanalysis. Each paper presented at the Discussion is summarized, and some personal thoughts as to the significance of the findings, the technical advances that made the experiments possible, and common themes between articles are interspersed...
October 20, 2016: Faraday Discussions
Bhaskar Dudem, Yeong Hwan Ko, Jung Woo Leem, Joo Ho Lim, Jae Su Yu
We report the hierarchical nano/micro architectured (HNMA)-polydimethylsiloxane (PDMS) film-based hybrid energy cells with multi-functionality to simultaneously harvest mechanical, solar, and wind energies. These films consist of nano/micro dual-scale architectures (i.e., nanonipples on inverted micro pyramidal arrays) on the PDMS surface. The HNMA-PDMS is replicable by a facile and cost-effective soft imprint lithography (SIL) using a nanoporous anodic alumina oxide (AAO) film formed on the micro-pyramidal (MP) structured silicon substrate...
October 19, 2016: ACS Applied Materials & Interfaces
Katie A Cychosz, Rémy Guillet-Nicolas, Javier García-Martínez, Matthias Thommes
This review focuses on important aspects of applying physisorption for the pore structural characterization of hierarchical materials such as mesoporous zeolites. During the last decades major advances in understanding the adsorption and phase behavior of fluids confined in ordered nanoporous materials have been made, which led to major progress in the physisorption characterization methodology (summarized in the 2015 IUPAC report on physisorption characterization). Here we discuss progress and challenges for the physisorption characterization of nanoporous solids exhibiting various levels of porosity from micro- to macropores...
October 19, 2016: Chemical Society Reviews
Cristina Zennaro, Maria Pia Rastaldi, Gerald James Bakeine, Riccarda Delfino, Federica Tonon, Rossella Farra, Gabriele Grassi, Mary Artero, Massimo Tormen, Michele Carraro
Although it is well recognized that cell-matrix interactions are based on both molecular and geometrical characteristics, the relationship between specific cell types and the three-dimensional morphology of the surface to which they are attached is poorly understood. This is particularly true for glomerular podocytes - the gatekeepers of glomerular filtration - which completely enwrap the glomerular basement membrane with their primary and secondary ramifications. Nanotechnologies produce biocompatible materials which offer the possibility to build substrates which differ only by topology in order to mimic the spatial organization of diverse basement membranes...
2016: International Journal of Nanomedicine
Yang Ruan, Yudan Zhu, Yumeng Zhang, Qingwei Gao, Xiaohua Lu, Linghong Lu
Residual Mg2+ could reduce the performance of lithium-ion batteries, but separating Mg2+ and Li+ is difficult because of their similar ionic properties. Inspired by the high selectivity of biological Mg2+ channels, this work investigates the ability of graphene-based nanopores with different diameters (0.789, 1.024 and 1.501 nm) to separate Mg2+ and Li+ under a series of transmembrane voltages using atomistic simulations. We analyzed the spatial distribution of molecules in the pore vicinity, ionic hydration structure properties, and potential of mean force of ions traveling through the nanopores...
October 18, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Sheng Luo, Jodie L Lutkenhaus, Hadi Nasrabadi
For over a century, the phase behavior of bulk fluids has been described as PVT (pressure-volume-temperature) three-dimensional properties, but it has become increasingly clear that the liquid-vapor phase behavior in confined geometries is significantly altered from the bulk. Efforts have been devoted to accessing confined phase transitions using sorption, molecular simulations and theoretical methods. However, a comprehensive picture of PVT relationships for confined hydrocarbons remains uncertain. Herein, we introduce d (confining pore diameter) as a fourth dimension, and we present PVT-d behavior of confined fluids in nanopores...
October 18, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Sang Jun Lee, Ji Yoon Kang, Wonjoon Choi, Rhokyun Kwak
Nanofluidic resistive pulse sensing (RPS) has been extensively used to measure the size, concentration, and surface charge of nanoparticles in electrically conducting solutions. Although various methods have been explored for improving detection performances, intrinsic problems including the extremely low particle-to-pore volume ratio (<0.01%) and fast nanoparticle translocation (10-1000 µs) still induce difficulties in detection, such as low signal magnitudes and short translocation times. Herein, we present an aqueous two-phase system (ATPS) in a nanofluidic RPS for amplifying translocation signals and decreasing translocation speeds simultaneously...
October 18, 2016: Small
Mélanie V Trudel, Antony T Vincent, Sabrina A Attéré, Myriam Labbé, Nicolas Derome, Alexander I Culley, Steve J Charette
The bacterium Aeromonas salmonicida subsp. salmonicida is a common pathogen in fish farms worldwide. Since the antibiotic resistance of this bacterial species is on the increase, it is important to have a broader view on this issue. In the present study, we tested the presence of known plasmids conferring multi-drug resistance as well as antibiotic resistance genes by a PCR approach in 100 Canadian A. salmonicida subsp. salmonicida isolates. Our study highlighted the dominance of the conjugative pSN254b plasmid, which confers multi-drug resistance...
October 18, 2016: Scientific Reports
Jeonghun Kim, Christine Young, Jaewoo Lee, Min-Sik Park, Mohammed Shahabuddin, Yusuke Yamauchi, Jung Ho Kim
Carbon nanotubes (CNT) grown on nanoporous carbon (NPC), which yields coexisting amorphous and graphitic nanoarchitectures, have been prepared on a large scale from zeolitic imidazolate framework (ZIF) by introducing bimetallic ions (Co(2+) and Zn(2+)). Interestingly, the hybrid Co/Zn-ZIF-derived NPC showed rich graphitic CNTs on the surface. This NPC was utilized for a coin-type supercapacitor cell with an aqueous electrolyte, which showed enhanced retention at high current density and good stability over 10 000 cycles...
October 17, 2016: Chemical Communications: Chem Comm
James Wilson, Leila Sloman, Zhiren He, Aleksei Aksimentiev
An inexpensive, reliable method for protein sequencing is essential to unraveling the biological mechanisms governing cellular behavior and disease. Current protein sequencing methods suffer from limitations associated with the size of proteins that can be sequenced, the time, and the cost of the sequencing procedures. Here, we report the results of all-atom molecular dynamics simulations that investigated the feasibility of using graphene nanopores for protein sequencing. We focus our study on the biologically significant phenylalanine-glycine repeat peptides (FG-nups)-parts of the nuclear pore transport machinery...
July 19, 2016: Advanced Functional Materials
Sarwar Beg, Mahfoozur Rahman, Atul Jain, Sumant Saini, Patrick Midoux, Chantal Pichon, Farhan Jalees Ahmad, Sohail Akhter
Metal organic frameworks (MOFs), porous hybrid polymer-metal composites at the nanoscale, are recent innovations in the field of chemistry; they are novel polymeric materials with diverse biomedical applications. MOFs are nanoporous materials, consisting of metal ions linked together by organic bridging ligands. The unique physical and chemical characteristics of MOFs have attracted wider attention from the scientific community, exploring their utility in the field of material science, biology, nanotechnology and drug delivery...
October 11, 2016: Drug Discovery Today
Yong Hee Kim, Gook Hwa Kim, Min Sun Kim, Sang-Don Jung
A Multi-electrode array (MEA) was fabricated with electrodes consisting of iridium oxide (IrOx) electrochemically deposited on nanoporous gold (NPG) to improve the moderate charge injection limit (ca. 1 mC cm-2) of NPG MEA. IrOx was electrodeposited by performing cyclic voltammetry with an IrOx deposition solution. The IrOx was electrodeposited on Au (EIROF/Au) and on NPG (EIROF/NPG) MEA, and the samples were analyzed in terms of the charge injection limit, charge storage capacity (CSC), and electrochemical impedance...
October 13, 2016: Nano Letters
Dongmei Xi, Jizhen Shang, Enguo Fan, Jin-Mao You, Shusheng Zhang, Hua Wang
The accurate discrimination of microRNAs (miRNAs) with highly similar sequences would greatly facilitate the screening and early diagnosis of diseases. In the present work, a locked nucleic acid (LNA)-modified probe was designed and used for α-hemolysin (α-HL) nanopore to selectively and specifically identify miRNAs. The hybridization of the LNA probe with the target miRNAs generated unique long-lived signals in the nanopore thus facilitated an accurate discrimination of miRNAs with similar sequences, even a single-nucleotide difference...
October 13, 2016: Analytical Chemistry
Christine Young, Rahul R Salunkhe, Jing Tang, Chi-Chang Hu, Mohammed Shahabuddin, Ekrem Yanmaz, Md Shahriar A Hossain, Jung Ho Kim, Yusuke Yamauchi
Nanoporous carbon materials are a versatile source of carbons that would be useful in applications ranging from electronics to electrochemical energy storage. Here, we focus on nanoporous carbon materials prepared by direct carbonization of zeolitic imidazolate frameworks (ZIF-8) towards supercapacitor applications. Several types of nanoporous carbons have been prepared by varying the applied carbonization temperature. The symmetric devices assembled using nanoporous carbon electrodes were tested for their optimal performance in the electrolyte of sulfuric acid solution...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
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