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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
Pavel Y Apel, Valery V Bashevoy, Irina V Blonskaya, Nikolay E Lizunov, Oleg L Orelovitch, Christina Trautmann
The method of producing single track-etched conical nanopores has received considerable attention and found many applications in diverse fields such as biosensing, nanofluidics, information processing and others. The performance of an asymmetric nanopore is largely determined by its geometry, especially by the size and shape of its tip. In this paper we reconstruct the profiles of so-called conical pores fabricated by asymmetric chemical etching of ion tracks in polymer foil. Conductometric measurements during etching and field emission scanning electron microscopy examinations of the resulting pores were employed in order to determine the pore geometry...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Zuzana Benková, Pavol Námer, Peter Cifra
The combined effects of the channel asymmetry and the closed chain topology on the chain extension, structure factor, and the orientation correlations were studied using coarse-grained molecular dynamics simulations for moderate chain lengths. These effects are related to applications in linearization experiments with a DNA molecule in nanofluidic devices. According to the aspect ratio, the channels are classified as a stripe or slabs. The chain segments do not have any freedom to move in the direction of the narrowest stripe size, being approximately the same size as the segment size...
October 12, 2016: Soft Matter
Kislon Voïtchovsky
The behaviour of fluids confined in nanoscale gaps plays a central role in molecular science and nanofluidics, with applications ranging from biological function to multiscale printing, osmosis and filtration, lab-on-chip technology and friction reduction. Here atomic force microscopy is used to shear five different mixtures of hexadecane and squalane confined between the tip apex and atomically flat graphite. The shearing amplitudes are typically <2 nm, hence reflecting highly localised information at the interface...
October 14, 2016: Nanoscale
Junho Hwang, Sho Kataoka, Akira Endo, Hirofumi Daiguji
Nanofluidic energy harvesting systems have attracted interest in the field of battery application, particularly for miniaturized electrical devices, because they possess excellent energy conversion capability for their size. In this study, a mesoporous silica (MPS)-based nanofluidic energy harvesting system was fabricated and selective ion transport in mesopores as a function of the salt gradient was investigated. Aqueous solutions with three different kinds of monovalent electrolytes-KCl, NaCl, and LiCl-with different diffusion coefficients (D+) were considered...
September 21, 2016: Lab on a Chip
Shaurya Prakash, A T Conlisk
Nanoscale fluid transport through conduits in the 1-100 nm range is termed as nanofluidics. Over the past decade or so, significant scientific and technological advances have occurred in the domain of nanofluidics with a transverse external electrical signal through a dielectric layer permitting control over ionic and fluid flows in these nanoscale conduits. Consequently, this special class of nanofluidic devices is commonly referred to as field effect devices, analogous to the solid-state field effect transistors that form the basis for modern electronics...
October 5, 2016: Lab on a Chip
Jun Huang, Jianbo Zhang, Michael Eikerling
The emerging field of nanoprotonics is concerned with controlling proton distribution and transport in nanoporous media. These phenomena, dictated by the surface charging properties of the host medium, are of vital importance in porous electrodes for fuel cells, electrolysers, supercapacitors and nanofluidic devices. In this theoretical study, we explore the interplay of the metal charging relation with the proton density and oxygen reduction activity in a water-filled nanopore with walls made of platinum. We exploit a non-monotonic charging behavior derived from a refined structural model of the Pt-solution interface...
September 19, 2016: Faraday Discussions
Vitaly V Chaban, Eudes Eterno Fileti
A nanofluid (NF) is composed of a base liquid and suspended nanoparticles (NPs). High-performance NFs exhibit significantly better heat conductivities, as compared to their base liquids. In the present work, we applied all-atom molecular dynamics (MD) simulations to characterize diffusive and ballistic energy transfer mechanisms within nanodiamonds (NDs), carbon nanotubes (CNTs), and N-butylpyridinium tetrafluoroborate ionic liquid (IL). We showed that heat transfer within both NDs and CNTs is orders of magnitude faster than that in the surrounding IL, whereas diffusion of all particles in the considered NF is similar...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Prasenjit Kabi, Swetaprovo Chaudhuri, Saptarshi Basu
Surface patterning with functional colloids is an important research area due to its widespread applicability in domains ranging from nano-electronics, pharmaceutics, semi-conductors, photovoltaics among others. To this endeavour, we propose a low-cost patterning technique that aspires to eliminate the more expensive methodologies presently in practise. Using a simple document stamp on which patterns of any geometry can be embossed, we are able to print two-dimensional mm-scale "wall-less confinement" using ink based hydrophobic fence on any plasma treated superhydrophilic surface...
October 4, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Mehdi Bahiraei, Morteza Hangi
Hydrothermal characteristics of a temperature-sensitive magnetic nanofluid between two parallel plates are investigated in the presence of magnetic field produced by one or multiple line dipole(s) using the two-phase mixture model. As the nanofluid reaches the region where the magnetic field is applied, a rotation is developed due to the dependency of magnetization on temperature. This can lead to mixing in the flow and more uniform distribution of temperature due to the disturbance caused in the boundary layer, and consequently, enhancement in convective heat transfer...
December 2016: Nanoscale Research Letters
C Dhanapal, J Kamalakkannan, J Prakash, M Kothandapani
This paper analyzes the peristaltic flow of an incompressible micropolar nanofluid in a tapered asymmetric channel in the presence of thermal radiation and heat sources parameters. The rotation of the nanoparticles is incorporated in the flow model. The equations governing the nanofluid flow are modeled and exact solutions are managed under long wavelength and flow Reynolds number and long wavelength approximations. Explicit expressions of axial velocity, stream function, microrotation, nanoparticle temperature, and concentration have been derived...
2016: Applied Bionics and Biomechanics
Noreen Sher Akbar, Naeem Kazmi, Dharmendra Tripathi, Nazir Ahmed Mir
BACKGROUND AND OBJECTIVES: With ongoing interest in CNT nanofluids and materials in biotechnology, energy and environment, microelectronics, composite materials etc., the current investigation is carried out to analyze the effects of variable viscosity and thermal conductivity of CNT nanofluids flow driven by cilia induced movement through a circular cylindrical tube. Metachronal wave is generated by the beating of cilia and mathematically modeled as elliptical wave propagation by Blake (1971)...
November 2016: Computer Methods and Programs in Biomedicine
Mohammad Amin Alibakhshi, Binqi Liu, Zhiping Xu, Chuanhua Duan
Control of ionic current in a nanofluidic system and development of the elements analogous to electrical circuits have been the subject of theoretical and experimental investigations over the past decade. Here, we theoretically and experimentally explore a new technique for rectification of ionic current using asymmetric 2D nanochannels. These nanochannels have a rectangular cross section and a stepped structure consisting of a shallow and a deep side. Control of height and length of each side enables us to obtain optimum rectification at each ionic strength...
September 2016: Biomicrofluidics
Wang Peng, Youping Chen, Wu Ai, Dailin Zhang
A nanofluidic biosensor based on nanoreplica molding photonic crystal (PC) was proposed. UV epoxy PC was fabricated by nanoreplica molding on a master PC wafer. The nanochannels were sealed between the gratings on the PC surface and a taped layer. The resonance wavelength of PC-based nanofluidic biosensor was used for testing the sealing effect. According to the peak wavelength value of the sensor, an initial label-free experiment was realized with R6g as the analyte. When the PC-based biosensor was illuminated by a monochromatic light source with a specific angle, the resonance wavelength of the sensor will match with the light source and amplified the electromagnetic field...
December 2016: Nanoscale Research Letters
Xin Sui, Zhen Zhang, Zhenyu Zhang, Zhiwei Wang, Chao Li, Hao Yuan, Longcheng Gao, Liping Wen, Xia Fan, Lijun Yang, Xinru Zhang, Lei Jiang
pH-gated ion channels in cell membranes play important roles in the cell's physiological activities. Many artificial nanochannels have been fabricated to mimic the natural phenomenon of pH-gated ion transport. However, these nanochannels show pH sensitivity only within certain pH ranges. Wide-range pH sensitivity has not yet been achieved. Herein, for the first time, we provide a versatile strategy to increase the pH-sensitive range by using dual amphoteric nanochannels. In particular, amphoteric polymeric nanochannels with carboxyl groups derived from a block copolymer (BCP) precursor and nanochannels with hydroxyl groups made from anodic alumina oxide (AAO) were used...
October 10, 2016: Angewandte Chemie
Joris Lacroix, Sandrine Pélofy, Charline Blatché, Marie-Jeanne Pillaire, Sébastien Huet, Catherine Chapuis, Jean-Sébastien Hoffmann, Aurélien Bancaud
DNA replication is essential to maintain genome integrity in S phase of the cell division cycle. Accumulation of stalled replication forks is a major source of genetic instability, and likely constitutes a key driver of tumorigenesis. The mechanisms of regulation of replication fork progression have therefore been extensively investigated, in particular with DNA combing, an optical mapping technique that allows the stretching of single molecules and the mapping of active region for DNA synthesis by fluorescence microscopy...
September 14, 2016: Small
Dong Hwan Shin, Jeffrey S Allen, Seong Hyuk Lee, Chang Kyoung Choi
Using a unique, near-field microscopy technique, fringe patterns and nanoparticle motions are visualized immediately following a nanofluid droplet deposition on a glass substrate in which an air bubble is entrapped. The nanofluid consists of DI-water, 0.10% Aluminum Oxide nanoparticles with an average diameter of 50 nm, and 0.0005% yellow-green polystyrene fluorescent particles of 1 μm diameter. High-speed, fluorescent-mode confocal imaging enables investigation of depth-wise sectioned particle movements in the nanofluid droplet inside which a bubble is entrapped...
2016: Scientific Reports
Eleonora Secchi, Sophie Marbach, Antoine Niguès, Derek Stein, Alessandro Siria, Lydéric Bocquet
Measurements and simulations have found that water moves through carbon nanotubes at exceptionally high rates owing to nearly frictionless interfaces. These observations have stimulated interest in nanotube-based membranes for applications including desalination, nano-filtration and energy harvesting, yet the exact mechanisms of water transport inside the nanotubes and at the water-carbon interface continue to be debated because existing theories do not provide a satisfactory explanation for the limited number of experimental results available so far...
September 7, 2016: Nature
Bernhard Wolfrum, Enno Kätelhön, Alexey Yakushenko, Kay J Krause, Nouran Adly, Martin Hüske, Philipp Rinklin
Micro- and nanofabriation technologies have a tremendous potential for the development of powerful sensor array platforms for electrochemical detection. The ability to integrate electrochemical sensor arrays with microfluidic devices nowadays provides possibilities for advanced lab-on-a-chip technology for the detection or quantification of multiple targets in a high-throughput approach. In particular, this is interesting for applications outside of analytical laboratories, such as point-of-care (POC) or on-site water screening where cost, measurement time, and the size of individual sensor devices are important factors to be considered...
September 20, 2016: Accounts of Chemical Research
B Radha, A Esfandiar, F C Wang, A P Rooney, K Gopinadhan, A Keerthi, A Mishchenko, A Janardanan, P Blake, L Fumagalli, M Lozada-Hidalgo, S Garaj, S J Haigh, I V Grigorieva, H A Wu, A K Geim
Nanometre-scale pores and capillaries have long been studied because of their importance in many natural phenomena and their use in numerous applications. A more recent development is the ability to fabricate artificial capillaries with nanometre dimensions, which has enabled new research on molecular transport and led to the emergence of nanofluidics. But surface roughness in particular makes it challenging to produce capillaries with precisely controlled dimensions at this spatial scale. Here we report the fabrication of narrow and smooth capillaries through van der Waals assembly, with atomically flat sheets at the top and bottom separated by spacers made of two-dimensional crystals with a precisely controlled number of layers...
September 7, 2016: Nature
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