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Abdallah BG, Roy-Chowdhury S, Coe J, Fromme P, Ros A. High throughput protein nanocrystal fractionation in a microfluidic sorter. Anal Chem 2015; 87:4159-67. [PMID: 25794348 DOI: 10.1021/acs.analchem.5b00589] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Protein crystallography is transitioning into a new generation with the introduction of the X-ray free electron laser, which can be used to solve the structures of complex proteins via serial femtosecond crystallography. Sample characteristics play a critical role in successful implementation of this new technology, whereby a small, narrow protein crystal size distribution is desired to provide high quality diffraction data. To provide such a sample, we developed a microfluidic device that facilitates dielectrophoretic sorting of heterogeneous particle mixtures into various size fractions. The first generation device demonstrated great potential and success toward this endeavor; thus, in this work, we present a comprehensive optimization study to improve throughput and control over sorting outcomes. First, device geometry was designed considering a variety of criteria, and applied potentials were modeled to determine the scheme achieving the largest sorting efficiency for isolating nanoparticles from microparticles. Further, to investigate sorting efficiency within the nanoparticle regime, critical geometrical dimensions and input parameters were optimized to achieve high sorting efficiencies. Experiments revealed fractionation of nanobeads from microbeads in the optimized device with high sorting efficiencies, and protein crystals were sorted into submicrometer size fractions as desired for future serial femtosecond crystallography experiments.
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Affiliation(s)
- Bahige G Abdallah
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States.,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Shatabdi Roy-Chowdhury
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States.,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Jesse Coe
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States.,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Petra Fromme
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States.,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Alexandra Ros
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States.,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
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52
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Cao Z, Yobas L. Gel-free electrophoresis of DNA and proteins on chips featuring a 70 nm capillary-well motif. ACS NANO 2015; 9:427-435. [PMID: 25535934 DOI: 10.1021/nn505605e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present an integrated glass capillary system on silicon for size-based sieving of distinct mixtures of proteins, short DNA, and long DNA fragments into sharp peaks. The minimum resolvable size difference achieved is noted as 3.45 kDa for 45-52.8 kDa proteins, 20 bp for 200-300 bp DNA strands, and 182 bp for 5.6-5.8 kbp DNA chains. This high-resolution sieving arises from vastly steep entropic barriers created at the onsets of extremely restrictive (resistive) capillary segments and their pivotal role in shifting the equilibrium entropic sieving to intense fields (>1000 V/cm). DNA fragments of various sizes are shown fully resolved in less than 7 min at a steady voltage of 2000 V being directly applied across the length of a 2 cm long sieve featuring thousands of entropic barriers. The utility of higher field strengths and longer sieves is also demonstrated without triggering dielectric breakdown by time-division multiplexing up to 2000 V across the 1 cm long sieve segments. The self-enclosed 70 nm diameter capillaries were fabricated using coarse (>1 μm) photolithography and standard semiconductor manufacturing techniques.
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Affiliation(s)
- Zhen Cao
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
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53
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Choi E, Kwon K, Kim D, Park J. An electrokinetic study on tunable 3D nanochannel networks constructed by spatially controlled nanoparticle assembly. LAB ON A CHIP 2015; 15:512-523. [PMID: 25407418 DOI: 10.1039/c4lc00949e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This paper proposes a novel method to form ion-selective nanochannel networks between two microfluidic channels using geometrically controlled in situ self-assembled nanoparticles. We present a thorough experimental and theoretical analysis of nanoscale electrokinetics using the proposed microplatform. The nano-interstices between these assembled nanoparticles serve as the nanopores of ion-selective membranes with equivalent pore size. Its inherent characteristics (compared with the conventional one-dimensional nanochannels) are a high ionic flux and a low fluidic resistance because these nanopore clusters have a role as collective three-dimensional nanochannel networks, which result in a highly efficient performance beneficial for various applications. Another uniqueness of our system is that the electrical characteristics (such as ion transport through the nanochannel networks and the decrease in the limiting current region) can be tuned quantitatively or even optimized by changing the geometry of the microchannel and the pH condition of the working solution or by appropriately selecting the size and materials of the assembled nanoparticles. The correlation between these tuning parameters and nanoscale electrokinetics is deeply investigated with carefully designed experiments and their mechanism is thoroughly examined by a theoretical study. We expect that the presented system and methodology can contribute to opening new application fields, such as biomolecule separation/filtering/accumulation/analysis, bioelectronics, and energy generation.
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Affiliation(s)
- Eunpyo Choi
- Department of Mechanical Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul, 121-742, Korea.
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54
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Osmanović D, Kerr-Winter M, Eccleston RC, Hoogenboom BW, Ford IJ. Effects of rotational symmetry breaking in polymer-coated nanopores. J Chem Phys 2015; 142:034901. [DOI: 10.1063/1.4905719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- D. Osmanović
- London Centre for Nanotechnology (LCN) and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - M. Kerr-Winter
- Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - R. C. Eccleston
- Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - B. W. Hoogenboom
- London Centre for Nanotechnology (LCN) and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - I. J. Ford
- London Centre for Nanotechnology (LCN) and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
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55
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Choi E, Kwon K, Kim D, Park J. Tunable reverse electrodialysis microplatform with geometrically controlled self-assembled nanoparticle network. LAB ON A CHIP 2015; 15:168-78. [PMID: 25328008 DOI: 10.1039/c4lc01031k] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Clean and sustainable energy generation from ambient environments is important not only for large scale systems, but also for tiny electrical devices, because of the limitations of batteries or external power sources. Chemical concentration gradients are promising energy resources to power micro/nanodevices sustainably without discharging any pollutants. In this paper, an efficient microplatform based on reverse electrodialysis, which enables high ionic flux through three dimensional nanochannel networks for high power energy generation, is demonstrated. Highly effective cation-selective nanochannel networks are realized between two microfluidic channels with geometrically controlled in situ self-assembled nanoparticles in a cost-effective and simple way. The nano-interstices between the assembled nanoparticles have a role as collective three-dimensional nanochannel networks and they allow higher ionic flux under concentration gradients without decreasing diffusion potential, compared to standard one-dimensional nanochannels. An in-depth experimental study with theoretical analysis shows that the electrical power of the presented system can be flexibly tuned or further optimized by changing the size, material, and shape of the assembled nanoparticles or by the geometric control of the microchannel. This microfluidic power generation system can be readily integrated with existing lab on a chip systems in the near future and can also be utilized to investigate nanoscale electrokinetics.
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Affiliation(s)
- Eunpyo Choi
- Department of Mechanical Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul, 121-742, Korea.
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56
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Yan S, Zhang J, Yuan Y, Lovrecz G, Alici G, Du H, Zhu Y, Li W. A hybrid dielectrophoretic and hydrophoretic microchip for particle sorting using integrated prefocusing and sorting steps. Electrophoresis 2014; 36:284-91. [DOI: 10.1002/elps.201400397] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 09/25/2014] [Accepted: 10/13/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Sheng Yan
- School of Mechanical; Materials and Mechatronic Engineering; University of Wollongong; Wollongong Australia
| | - Jun Zhang
- School of Mechanical; Materials and Mechatronic Engineering; University of Wollongong; Wollongong Australia
| | - Yuan Yuan
- School of Materials Science and Engineering; University of New South Wales; Sydney Australia
| | | | - Gursel Alici
- School of Mechanical; Materials and Mechatronic Engineering; University of Wollongong; Wollongong Australia
| | - Haiping Du
- School of Electric; Computer and Telecommunication Engineering; University of Wollongong; Wollongong Australia
| | - Yonggang Zhu
- CSIRO Manufacturing Flagship; Clayton Australia
- Melbourne Centre for Nanofabrication/Australian National Fabrication Facility; Clayton Australia
| | - Weihua Li
- School of Mechanical; Materials and Mechatronic Engineering; University of Wollongong; Wollongong Australia
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57
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DesOrmeaux JPS, Winans JD, Wayson SE, Gaborski TR, Khire TS, Striemer CC, McGrath JL. Nanoporous silicon nitride membranes fabricated from porous nanocrystalline silicon templates. NANOSCALE 2014; 6:10798-10805. [PMID: 25105590 DOI: 10.1039/c4nr03070b] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The extraordinary permeability and manufacturability of ultrathin silicon-based membranes are enabling devices with improved performance and smaller sizes in such important areas as molecular filtration and sensing, cell culture, electroosmotic pumping, and hemodialysis. Because of the robust chemical and mechanical properties of silicon nitride (SiN), several laboratories have developed techniques for patterning nanopores in SiN using reactive ion etching (RIE) through a template structure. These methods however, have failed to produce pores small enough for ultrafiltration (<100 nm) in SiN and involve templates that are prone to microporous defects. Here we present a facile, wafer-scale method to produce nanoporous silicon nitride (NPN) membranes using porous nanocrystalline silicon (pnc-Si) as a self-assembling, defect free, RIE masking layer. By modifying the mask layer morphology and the RIE etch conditions, the pore sizes of NPN can be adjusted between 40 nm and 80 nm with porosities reaching 40%. The resulting NPN membranes exhibit higher burst pressures than pnc-Si membranes while having 5× greater permeability. NPN membranes also demonstrate the capacity for high resolution separations (<10 nm) seen previously with pnc-Si membranes. We further demonstrate that human endothelial cells can be grown on NPN membranes, verifying the biocompatibility of NPN and demonstrating the potential of this material for cell culture applications.
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58
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Osmanović D, Ford IJ, Hoogenboom BW. Model inspired by nuclear pore complex suggests possible roles for nuclear transport receptors in determining its structure. Biophys J 2014; 105:2781-9. [PMID: 24359750 DOI: 10.1016/j.bpj.2013.11.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/25/2013] [Accepted: 11/04/2013] [Indexed: 12/20/2022] Open
Abstract
Nuclear transport receptors (NTRs) mediate nucleocytoplasmic transport via their affinity for unstructured proteins (polymers) in the nuclear pore complex (NPC). Here, we have modeled the effect of NTRs on polymeric structure in the nanopore confinement of the NPC central conduit. The model explicitly takes into account inter- and intramolecular interactions, as well as the finite size of the NTRs (∼20% of the NPC channel diameter). It reproduces various proposed scenarios for the channel structure, ranging from a central polymer condensate (selective phase) to brushlike polymer arrangements localized at the channel wall (virtual gate, reduction of dimensionality), with the transport receptors lining the polymer surface. In addition, it predicts a new structure in which NTRs become an integral part of the transport barrier by forming a cross-linked network with the unstructured proteins stretching across the pore. The model provides specific and distinctive predictions for the equilibrium spatial distributions of NTRs for these different scenarios that can be experimentally verified by, e.g., superresolution fluorescence microscopy. Moreover, it suggests mechanisms by which globular macromolecules (colloidal particles) can cause polymer-coated nanopores to switch between open and closed configurations, a possible explanation of the biological function of the NPC, and suggests potential technological applications for filtration and single-molecule sensing.
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Affiliation(s)
- Dino Osmanović
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, United Kingdom.
| | - Ian J Ford
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Bart W Hoogenboom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, United Kingdom
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59
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Trejos VM, Gil-Villegas A, Martinez A. Computer simulation of liquid-vapor coexistence of confined quantum fluids. J Chem Phys 2014; 139:184505. [PMID: 24320282 DOI: 10.1063/1.4829769] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The liquid-vapor coexistence (LV) of bulk and confined quantum fluids has been studied by Monte Carlo computer simulation for particles interacting via a semiclassical effective pair potential Veff(r) = VLJ + VQ, where VLJ is the Lennard-Jones 12-6 potential (LJ) and VQ is the first-order Wigner-Kirkwood (WK-1) quantum potential, that depends on β = 1∕kT and de Boer's quantumness parameter Λ=h/σ√mε, where k and h are the Boltzmann's and Planck's constants, respectively, m is the particle's mass, T is the temperature of the system, and σ and ε are the LJ potential parameters. The non-conformal properties of the system of particles interacting via the effective pair potential Veff(r) are due to Λ, since the LV phase diagram is modified by varying Λ. We found that the WK-1 system gives an accurate description of the LV coexistence for bulk phases of several quantum fluids, obtained by the Gibbs Ensemble Monte Carlo method (GEMC). Confinement effects were introduced using the Canonical Ensemble (NVT) to simulate quantum fluids contained within parallel hard walls separated by a distance Lp, within the range 2σ ≤ Lp ≤ 6σ. The critical temperature of the system is reduced by decreasing Lp and increasing Λ, and the liquid-vapor transition is not longer observed for Lp∕σ < 2, in contrast to what has been observed for the classical system.
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Affiliation(s)
- Víctor M Trejos
- División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Guanajuato, Mexico
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60
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Agonafer DD, Oruc ME, Chainani E, Lee KS, Hu H, Shannon MA. Study of ionic transport through metalized nanoporous membranes functionalized with self-assembled monolayers. J Memb Sci 2014. [DOI: 10.1016/j.memsci.2014.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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61
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Collins DJ, Alan T, Neild A. Particle separation using virtual deterministic lateral displacement (vDLD). LAB ON A CHIP 2014; 14:1595-603. [PMID: 24638896 DOI: 10.1039/c3lc51367j] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We present a method for sensitive and tunable particle sorting that we term virtual deterministic lateral displacement (vDLD). The vDLD system is composed of a set of interdigital transducers (IDTs) within a microfluidic chamber that produce a force field at an angle to the flow direction. Particles above a critical diameter, a function of the force induced by viscous drag and the force field, are displaced laterally along the minimum force potential lines, while smaller particles continue in the direction of the fluid flow without substantial perturbations. We demonstrate the effective separation of particles in a continuous-flow system with size sensitivity comparable or better than other previously reported microfluidic separation techniques. Separation of 5.0 μm from 6.6 μm, 6.6 μm from 7.0 μm and 300 nm from 500 nm particles are all achieved using the same device architecture. With the high sensitivity and flexibility vDLD affords we expect to find application in a wide variety of microfluidic platforms.
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Affiliation(s)
- David J Collins
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
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62
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Lee DS, Song HW, Choi CG, Jung MY. Pore-size reduction protocol for SiN membrane nanopore using the thermal reflow in nanoimprinting for nanobio-based sensing. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:051211. [PMID: 24503699 DOI: 10.1117/1.jbo.19.5.051211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 12/26/2013] [Indexed: 06/03/2023]
Abstract
Micro- and nano-fabrication methods facilitate the use of nanostructures for the separation of collections of particles and nanobio-based optical and electrochemical sensing. We have presented an easy and simple nanopore size reduction method of a low-stressed silicon nitride (SiN) membrane nanosieve (100×100 μm2) using a nanoimprinting method based on a natural thermal reflow of the contact imprinting polymer, possibly maintaining compatibility with complementary metal-oxide semiconductor integrated circuit processes. The nanopore pattern size of this nanosieve membrane was precisely patterned by a nanoimprinting process using an electron beam patterned silicon master, to about 30-nm diameter. By employing mainly an electron beam resist reflow phenomena after a nanoimprinting process and anisotropic reactive ion etch, the etch holes' size was fabricated to be the same with nanopatterns on the polymer. The contact imprinting master can be used continually for the generation of nanopore patterns simply and easily. It can endure harsh conditions like high temperature up to 800°C, and it is inert to many aggressive and strong chemicals. Also, this would be a low-cost, simple, and easy fabrication method for the precise and reliable size-reduction control of nanopores for mass production of nanobio sensors or chips.
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Affiliation(s)
- Dae-Sik Lee
- Electronics and Telecommunication Research Institute, IT Convergence Components Laboratory, Daejeon 305-700, Republic of Korea
| | - Hyun-Woo Song
- Electronics and Telecommunication Research Institute, IT Convergence Components Laboratory, Daejeon 305-700, Republic of Korea
| | - Choon-Gi Choi
- Creative Research Center for Graphene Electronics, ETRI, Daejeon 305-700, Republic of Korea
| | - Mun Youn Jung
- Electronics and Telecommunication Research Institute, IT Convergence Components Laboratory, Daejeon 305-700, Republic of Korea
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63
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Jeng PR, Chen K, Hwang GJ, Cho EY, Lien C, To K, Chou YC. Entropic force on granular chains self-extracting from one-dimensional confinement. J Chem Phys 2014; 140:024912. [PMID: 24437916 DOI: 10.1063/1.4861559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The entropic forces on the self-retracting granular chains, which are confined in channels with different widths, are determined. The time dependence of the length of chain remaining in the channel Lin(t) is measured. The entropic force is treated as the only parameter in fitting the solution of the nonlinear equation of motion of Lin(t) to the experimental data. The dependence of the entropic force on the width of the confining channel can be expressed as a power-law with an exponent of 1.3, which is consistent with the previous theoretical predictions for the entropy loss due to confinement.
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Affiliation(s)
- Pei-Ren Jeng
- Institute of Electronics Engineering, National Tsing-Hua University, Hsin-chu 30042, Taiwan
| | - KuanHua Chen
- Department of Physics, National Tsing-Hua University, Hsinchu 30042, Taiwan
| | - Gwo-jen Hwang
- Department of Electronic Engineering, St. John's University, Tamsui 25135, Taiwan
| | - Ethan Y Cho
- Department of Physics, National Tsing-Hua University, Hsinchu 30042, Taiwan
| | - Chenhsin Lien
- Institute of Electronics Engineering, National Tsing-Hua University, Hsin-chu 30042, Taiwan
| | - Kiwing To
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Y C Chou
- Department of Physics, National Tsing-Hua University, Hsinchu 30042, Taiwan
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64
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Fu G, Su Z, Jiang X, Yin J. Photo-crosslinked nanofibers of poly(ether amine) (PEA) for the ultrafast separation of dyes through molecular filtration. Polym Chem 2014. [DOI: 10.1039/c3py01443f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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65
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Zhu C, Li H, Zeng XC, Wang EG, Meng S. Quantized water transport: ideal desalination through graphyne-4 membrane. Sci Rep 2013; 3:3163. [PMID: 24196437 PMCID: PMC3819615 DOI: 10.1038/srep03163] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 10/23/2013] [Indexed: 11/09/2022] Open
Abstract
Graphyne sheet exhibits promising potential for nanoscale desalination to achieve both high water permeability and salt rejection rate. Extensive molecular dynamics simulations on pore-size effects suggest that γ-graphyne-4, with 4 acetylene bonds between two adjacent phenyl rings, has the best performance with 100% salt rejection and an unprecedented water permeability, to our knowledge, of ~13 L/cm(2)/day/MPa, 3 orders of magnitude higher than prevailing commercial membranes based on reverse osmosis, and ~10 times higher than the state-of-the-art nanoporous graphene. Strikingly, water permeability across graphyne exhibits unexpected nonlinear dependence on the pore size. This counter-intuitive behavior is attributed to the quantized nature of water flow at the nanoscale, which has wide implications in controlling nanoscale water transport and designing highly effective membranes.
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Affiliation(s)
- Chongqin Zhu
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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66
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Lemaire T, Kaiser J, Naili S, Sansalone V. Textural versus electrostatic exclusion-enrichment effects in the effective chemical transport within the cortical bone: a numerical investigation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2013; 29:1223-1242. [PMID: 23804591 DOI: 10.1002/cnm.2571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/30/2013] [Accepted: 06/03/2013] [Indexed: 06/02/2023]
Abstract
Interstitial fluid within bone tissue is known to govern the remodelling signals' expression. Bone fluid flow is generated by skeleton deformation during the daily activities. Due to the presence of charged surfaces in the bone porous matrix, the electrochemical phenomena occurring in the vicinity of mechanosensitive bone cells, the osteocytes, are key elements in the cellular communication. In this study, a multiscale model of interstitial fluid transport within bone tissues is proposed. Based on an asymptotic homogenization method, our modelling takes into account the physicochemical properties of bone tissue. Thanks to this multiphysical approach, the transport of nutrients and waste between the blood vessels and the bone cells can be quantified to better understand the mechanotransduction of bone remodelling. In particular, it is shown that the electrochemical tortuosity may have stronger implications in the mass transport within the bone than the purely morphological one.
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Affiliation(s)
- T Lemaire
- Université Paris Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 61 Avenue du Général de Gaulle, 94010 Créteil, France
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67
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Nicolini C, Singh M, Spera R, Felli L. Analysis of gene expression on anodic porous alumina microarrays. Bioengineered 2013; 4:332-7. [PMID: 23783000 PMCID: PMC3813533 DOI: 10.4161/bioe.25278] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
This paper investigates the application of anodic porous alumina as an advancement on chip laboratory for gene expressions. The surface was prepared by a suitable electrolytic process to obtain a regular distribution of deep micrometric holes and printed bypen robot tips under standard conditions. The gene expression within the Nucleic Acid Programmable Protein Array (NAPPA) is realized in a confined environment of 16 spots, containing circular DNA plasmids expressed using rabbit reticulocyte lysate. Authors demonstrated the usefulness of APA in withholding the protein expression by detecting with a CCD microscope the photoluminescence signal emitted from the complex secondary antibody anchored to Cy3 and confined in the pores. Friction experiments proved the mechanical resistance under external stresses by the robot tip pens printing. So far, no attempts have been made to directly compare APA with any other surface/substrate; the rationale for pursuing APA as a potential surface coating is that it provides advantages over the simple functionalization of a glass slide, overcoming concerns about printing and its ability to generate viable arrays.
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Affiliation(s)
- Claudio Nicolini
- Nanoworld Institute; Fondazione EL.B.A. Nicolini; Pradalunga, Italy; Laboratories of Biophysics and Nanobiotechnology; Department of Experimental Medicine; University of Genova; Genova, Italy; Department of Surgical Sciences and Integrated Diagnostic; University of Genova; Genova, Italy
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68
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Hedayat A, Peace R, Elmoselhi H, Shoker A. Study of uremic toxin fluxes across nanofabricated hemodialysis membranes using irreversible thermodynamics. Comput Struct Biotechnol J 2013; 6:e201303005. [PMID: 24688713 PMCID: PMC3962091 DOI: 10.5936/csbj.201303005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 06/02/2013] [Accepted: 06/03/2013] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION The flux of uremic toxin middle molecules through currently used hemodialysis membranes is suboptimal, mainly because of the membranes' pore architecture. AIM Identifying the modifiable sieving parameters that can be improved by nanotechnology to enhance fluxes of uremic toxins across the walls of dialyzers' capillaries. METHODS We determined the maximal dimensions of endothelin, cystatin C, and interleukin - 6 using the macromolecular modeling software, COOT. We also applied the expanded Nernst-Plank equation to calculate the changes in the overall flux as a function of increased electro-migration and pH of the respective molecules. RESULTS In a high flux hemodialyzer, the effective diffusivities of endothelin, cystatin C, and interleukin - 6 are 15.00 x 10(-10) cm(2)/s, 7.7 x 10(-10) cm(2)/s, and 5.4 x 10(-10) cm(2)/s, respectively, through the capillaries' walls. In a nanofabricated membrane, the effective diffusivities of endothelin, cystatin C, and interleukin - 6 are 13.87 x 10(-7) cm(2)/s, 5.73 x 10(-7) cm(2)/s, and 3.45 x 10(-7) cm(2)/s, respectively, through a nanofabricated membrane. Theoretical modeling showed that a 96% reduction in the membrane's thickness and the application of an electric potential of 10 mV across the membrane could enhance the flux of endothelin, cystatin C, and interleukin - 6 by a factor of 25. A ΔpH of 0.07 altered the fluxes minimally. CONCLUSIONS Nanofabricated hemodialysis membranes with a reduced thickness and an applied electric potential can enhance the effective diffusivity and electro-migration flux of the respective uremic toxins by 3 orders of magnitude as compared to those passing through the high flux hemodialyzer.
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Affiliation(s)
- Assem Hedayat
- College of Dentistry, University of Saskatchewan, 105 Wiggins Road, Saskatoon, SK, S7N 5E4, Canada
| | - Rob Peace
- Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK, S7N 5A9, Canada
| | - Hamdi Elmoselhi
- Saskatchewan Transplant Program, St. Paul's Hospital, 1702, 20th Street West, Saskatoon, SK, S7M 0Z9, Canada
| | - Ahmed Shoker
- Saskatchewan Transplant Program, St. Paul's Hospital, 1702, 20th Street West, Saskatoon, SK, S7M 0Z9, Canada ; Division of Nephrology, Department of Medicine, University of Saskatchewan, 103 Hospital Drive, Saskatoon, SK, S7N 0W8, Canada
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69
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Mahadevan T, Kojic M, Ferrari M, Ziemys A. Mechanisms of reduced solute diffusivity at nanoconfined solid–liquid interface. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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70
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Charge-selective gate of arrayed MWCNTs for ultra high-efficient biomolecule enrichment by nano-electrostatic sieving (NES). Biosens Bioelectron 2013; 43:453-60. [DOI: 10.1016/j.bios.2012.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/02/2012] [Accepted: 12/03/2012] [Indexed: 11/19/2022]
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71
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Schnitzer O, Yariv E. Electric conductance of highly selective nanochannels. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:054301. [PMID: 23767659 DOI: 10.1103/physreve.87.054301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Indexed: 06/02/2023]
Abstract
We consider electric conductance through a narrow nanochannel in the thick-double-layer limit, where the space-charge Debye layers adjacent to the channel walls overlap. At moderate surface-charge densities the electrolyte solution filling the channel comprises mainly of counterions. This allows to derive an analytic closed-form approximation for the channel conductance, independent of the salt concentration in the channel reservoirs. The derived expression consists of two terms. The first, representing electromigratory transport, is independent of the channel depth. The second, representing convective transport, depends upon it weakly.
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Affiliation(s)
- Ory Schnitzer
- Department of Mathematics, Technion - Israel Institute of Technology, Technion City 32000, Israel
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72
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Warkiani ME, Bhagat AAS, Khoo BL, Han J, Lim CT, Gong HQ, Fane AG. Isoporous micro/nanoengineered membranes. ACS NANO 2013; 7:1882-1904. [PMID: 23442009 DOI: 10.1021/nn305616k] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Isoporous membranes are versatile structures with numerous potential and realized applications in various fields of science such as micro/nanofiltration, cell separation and harvesting, controlled drug delivery, optics, gas separation, and chromatography. Recent advances in micro/nanofabrication techniques and material synthesis provide novel methods toward controlling the detailed microstructure of membrane materials, allowing fabrication of membranes with well-defined pore size and shape. This review summarizes the current state-of-the-art for isoporous membrane fabrication using different techniques, including microfabrication, anodization, and advanced material synthesis. Various applications of isoporous membranes, such as protein filtration, pathogen isolation, cell harvesting, biosensing, and drug delivery, are also presented.
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Affiliation(s)
- Majid Ebrahimi Warkiani
- BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, Singapore.
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73
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Piguet F, Foster DP. Translocation of short and long polymers through an interacting pore. J Chem Phys 2013; 138:084902. [DOI: 10.1063/1.4792716] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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74
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Chen Z, Dorfman KD. Relationship between frequency and deflection angle in the DNA prism. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:012723. [PMID: 23410375 PMCID: PMC3597986 DOI: 10.1103/physreve.87.012723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/18/2012] [Indexed: 06/01/2023]
Abstract
The DNA prism is a modification of the standard pulsed-field electrophoresis protocol to provide a continuous separation, where the DNA are deflected at an angle that depends on their molecular weight. The standard switchback model for the DNA prism predicts a monotonic increase in the deflection angle as a function of the frequency for switching the field until a plateau regime is reached. However, experiments indicate that the deflection angle achieves a maximum value before decaying to a size-independent value at high frequencies. Using Brownian dynamics simulations, we show that the maximum in the deflection angle is related to the reorientation time for the DNA and the decay in deflection angle at high frequencies is due to inadequate stretching. The generic features of the dependence of the deflection angle on molecular weight, switching frequency, and electric field strength explain a number of experimental phenomena.
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Affiliation(s)
- Zhen Chen
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, MN 55455, USA
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, MN 55455, USA
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75
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Fu CL, Sun ZY, An LJ. The properties of a single polymer chain in solvent confined in a slit: A molecular dynamics simulation. CHINESE JOURNAL OF POLYMER SCIENCE 2012. [DOI: 10.1007/s10118-013-1231-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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76
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Morphological Characterization of the Polyflux 210H Hemodialysis Filter Pores. Int J Nephrol 2012; 2012:304135. [PMID: 23209902 PMCID: PMC3502870 DOI: 10.1155/2012/304135] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 10/09/2012] [Indexed: 11/17/2022] Open
Abstract
Background. Morphological characterization of hemodialysis membranes is necessary to improve pore design. Aim. To delineate membrane pore structure of a high flux filter, Polyflux 210H. Methods. We used a Joel JSM-6010LV scanning electron microscope (SEM) and a SU6600 Hitachi field emission scanning electron microscope (FESEM) to characterize the pore and fiber morphology. The maximal diameters of selected uremic toxins were calculated using the macromolecular modeling Crystallographic Object-Oriented Toolkit (COOT) software. Results. The mean pore densities on the outermost and innermost surfaces of the membrane were 36.81% and 5.45%, respectively. The membrane exhibited a tortuous structure with poor connection between the inner and outer pores. The aperture's width in the inner surface ranged between 34 and 45 nm, which is 8.76-11.60 times larger than the estimated maximum diameter of β2-microglobulin (3.88 nm). Conclusion. The results suggest that the diameter size of inner pore apertures is not a limiting factor to middle molecules clearance, the extremely diminished density is. Increasing inner pore density and improving channel structure are strategies to improve clearance of middle molecules.
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77
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Theoretical Application of Irreversible (Nonequilibrium) Thermodynamic Principles to Enhance Solute Fluxes across Nanofabricated Hemodialysis Membranes. Int J Nephrol 2012; 2012:718085. [PMID: 23209903 PMCID: PMC3502860 DOI: 10.1155/2012/718085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/19/2012] [Accepted: 08/06/2012] [Indexed: 11/17/2022] Open
Abstract
Objective. Nanotechnology has the potential to improve hemodialysis membrane technology. Thus, a major objective is to understand how to enhance toxic solute fluxes across these membranes. The aim of this concept building study is to review the application of irreversible thermodynamic (IT) to solute fluxes. Methods. We expanded the application of the Nernst-Planck equation to include the Kedem-Katchalsky equation, pH, membrane thickness, pore size, and electric potential as variables. Results. (1) Reducing the membrane's thickness from 25 μm to 25 nm increased the flux of creatinine, β2-microglobulin, and tumor necrosis factor-α (TNF-α) by a thousand times but prevented completely albumin flux, (2) applying an electric potential of 50–400 mV across the membrane enhanced the flux of the respective molecules by 71.167 × 10−3, 38.7905 × 10−8, and 0.595 × 10−13 mol/s, and (3) changing the pH from 7.35 to 7.42 altered the fluxes minimally. Conclusions. The results supported an argument to investigate the application of IT to study forces of fluxes across membranes. Reducing the membrane's thickness—together with the application of an electrical potential—qualities achievable by nanotechnology, can enhance the removal of uremic toxins by many folds. However, changing the pH at a specific membrane thickness does not affect the flux significantly.
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78
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An S, Stambaugh C, Kim G, Lee M, Kim Y, Lee K, Jhe W. Low-volume liquid delivery and nanolithography using a nanopipette combined with a quartz tuning fork-atomic force microscope. NANOSCALE 2012; 4:6493-6500. [PMID: 22960993 DOI: 10.1039/c2nr30972f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Electric-field-induced low-volume liquid ejection under ambient conditions was realized at a low bias potential of 12 V via a nanopipette (aperture diameter of 30 nm) combined with a non-contact, distance-regulated (within 10 nm) quartz tuning fork-atomic force microscope. A capillary-condensed water meniscus, spontaneously formed in the tip-substrate nanogap, reduces the ejection barrier by four orders of magnitude, facilitating nanoliquid ejection and subsequent liquid transport/dispersion onto the substrate without contact damage from the pipette. A study of nanofluidics through a free-standing liquid nanochannel and nanolithography was performed with this technique. This is an important breakthrough for various applications in controlled nanomaterial-delivery and selective deposition, such as multicolor nanopatterning and nano-inkjet devices.
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Affiliation(s)
- Sangmin An
- Department of Physics and Astronomy, Seoul National University, Daehak-dong, Gwanak-gu, Seoul 151-747, Republic of Korea
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79
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Quist J, Vulto P, van der Linden H, Hankemeier T. Tunable Ionic Mobility Filter for Depletion Zone Isotachophoresis. Anal Chem 2012; 84:9065-71. [DOI: 10.1021/ac301612n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jos Quist
- Leiden/Amsterdam Centre for Drug Research (LACDR), Division of Analytical
Biosciences, Einsteinweg 55, 2333CC, Leiden, The Netherlands
- Netherlands Metabolomics Centre (NMC), Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Paul Vulto
- Leiden/Amsterdam Centre for Drug Research (LACDR), Division of Analytical
Biosciences, Einsteinweg 55, 2333CC, Leiden, The Netherlands
- Netherlands Metabolomics Centre (NMC), Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Heiko van der Linden
- Leiden/Amsterdam Centre for Drug Research (LACDR), Division of Analytical
Biosciences, Einsteinweg 55, 2333CC, Leiden, The Netherlands
- Netherlands Metabolomics Centre (NMC), Einsteinweg 55, 2333CC, Leiden, The Netherlands
| | - Thomas Hankemeier
- Leiden/Amsterdam Centre for Drug Research (LACDR), Division of Analytical
Biosciences, Einsteinweg 55, 2333CC, Leiden, The Netherlands
- Netherlands Metabolomics Centre (NMC), Einsteinweg 55, 2333CC, Leiden, The Netherlands
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80
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81
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Velleman L, Losic D, Shapter JG. The effects of surface functionality positioning on the transport properties of membranes. J Memb Sci 2012. [DOI: 10.1016/j.memsci.2012.04.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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82
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Ziemys A, Kojic M, Milosevic M, Ferrari M. Interfacial effects on nanoconfined diffusive mass transport regimes. PHYSICAL REVIEW LETTERS 2012; 108:236102. [PMID: 23003974 PMCID: PMC3842168 DOI: 10.1103/physrevlett.108.236102] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Indexed: 05/24/2023]
Abstract
A hierarchical multiscale modeling approach, incorporating molecular dynamics and finite element techniques, is used to study parametrically diffusion regimes through nanoconfined fluid. Novel parameters that determine the character of the diffusion regime and diffusion kinetics within the nanoscale confined fluids is established by exploring diffusion where the interface effects at the solid surface are important. New diffusion transport characteristics are established when nanochannel confining dimension approaches 3-4 sizes of diffusing molecules, which also marks peripheries of the non-fickian transport regime.
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Affiliation(s)
- A Ziemys
- The Methodist Hospital Research Institute, The Department of Nanomedicine, 6670 Bertner Avenue, R7-116, Houston, Texas 77030, USA
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83
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ACHAR HVBALACHANDRA, BHATTACHARYA ENAKSHI. NANOPOROUS SILICON MEMBRANE FOR BIOMOLECULAR SEPARATION. INTERNATIONAL JOURNAL OF NANOSCIENCE 2012. [DOI: 10.1142/s0219581x11008915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Separation of biomolecules based on their size and charge is an important procedure employed in biomolecular analysis. Nanosieve comprising of a semi-permeable membrane with nanometer-sized pores is used for this purpose. Described here is the fabrication of ultra thin nanoporous silicon membrane, which can be used as nanosieve, making use of standard microelectronics fabrication techniques. Lithography and bulk silicon etching is used to initially create a 10 μm thick sacrificial membrane in the center of a 200 μm thick silicon substrate. A three-layer stack of SiO2 , amorphous silicon ( a-Si ) and SiO2 is then deposited using chemical vapor deposition technique. The sample is subjected to rapid thermal annealing during which pores are formed in the a-Si layer. Finally, the 15 nm thick nanoporous silicon membrane is released using reactive ion etching of the sacrificial membrane. The formation of the pores is confirmed by transmission and scanning electron microscope images. At present the pore formation is random; our future work will focus on controlled nucleation of silicon nanocrystals so as to get pores at desired locations.
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Affiliation(s)
- H. V. BALACHANDRA ACHAR
- Microelectronics and MEMS Laboratory, Electrical Engineering Department, Indian Institute of Technology Madras, Chennai 600 036, India
| | - ENAKSHI BHATTACHARYA
- Microelectronics and MEMS Laboratory, Electrical Engineering Department, Indian Institute of Technology Madras, Chennai 600 036, India
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84
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Abstract
Synthetic nanoporous membranes have been used in numerous biosensing applications, such as glucose detection, nucleic acid detection, bacteria detection, and cell-based sensing. The increased surface affinity area and enhanced output sensing signals make the nanoporous membranes increasingly attractive as biosensing platforms. Surface modification techniques can be used to improve surface properties for realizable bioanalyte immobilization, conjugation, and detection. Combined with realizable detection techniques such as electrochemical and optical detection methods, nanoporous membrane–based biosensors have advantages, including rapid response, high sensitivity, and low cost. In this paper, an overview of nanoporous membranes for biosensing application is given. Types of nanoporous membranes including polymer membranes, inorganic membranes, membranes with nanopores fabricated using nanolithography, and nanotube-based membranes are introduced. The fabrication techniques of nanoporous membranes are also discussed. The key requirements of nanoporous membranes for biosensing applications include surface functionality for bioanalyte immobilization, biocompatibility, mechanical and chemical stability, and anti-biofouling capability. The recent advances and development of nanoporous membrane–based biosensors are discussed, especially for the sensing mechanism and surface functionalization strategies. Finally, the challenges and future development of nanoporous membrane for biosensing applications are discussed.
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Affiliation(s)
- YANG MO
- Department of Health Technology and Informatics, Biomedical Engineering Programme, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - TAN FEI
- Department of Health Technology and Informatics, Biomedical Engineering Programme, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
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85
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Seo J, Lee TJ, Ko S, Yeo H, Kim S, Noh T, Song S, Sung MM, Lee H. Hierarchical and multifunctional three-dimensional network of carbon nanotubes for microfluidic applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:1975-1979. [PMID: 22422430 DOI: 10.1002/adma.201104958] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 01/16/2012] [Indexed: 05/31/2023]
Abstract
Three-Dimensional network of carbon nanotubes: The 3D network of CNTs have hierarchical structures comprised of interconnected SWNTs between Si pillars in microfluidic channels. The Al(2)O(3) coated 3D networks were used for size different nanoparticles filtration and streptavidin capturing in very diluted solution. The 3D network of SWNTs systems will provide a robust multifuncitonal platform for a variety of biomedical and environmental applications.
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Affiliation(s)
- Jeongeun Seo
- Department of Chemistry, Hanyang University, Seoul 133-791, Korea
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86
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Verleger S, Grimm A, Kreuter C, Tan HM, van Kan JA, Erbe A, Scheer E, van der Maarel JRC. A single-channel microparticle sieve based on Brownian ratchets. LAB ON A CHIP 2012; 12:1238-1241. [PMID: 22344460 DOI: 10.1039/c2lc21089d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a novel device for the separation of microparticles in a single channel, which is made of inversely asymmetric Brownian ratchets. It enables separation into two different fractions with an adjustable threshold and can be modeled with good agreement. This device serves as proof of concept for an extremely compact class of microsieves.
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Affiliation(s)
- Simon Verleger
- Fachbereich Physik, University Konstanz, D-78457 Konstanz, Germany.
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87
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Lemaire T, Naili S. Possible role of calcium permselectivity in bone adaptation. Med Hypotheses 2012; 78:367-9. [PMID: 22222154 DOI: 10.1016/j.mehy.2011.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 12/09/2011] [Indexed: 11/15/2022]
Abstract
According to the core activity of calcium in the bone cellular expression, a new hypothesis linking calcium transport with the mechanical loading is proposed to explain the mechano-adaptation of bone tissue. Due to the piezoelectric coupling, the tensile and compressive areas of bone produce different electrical environments for the osteocytic cells that are embedded in the lacuno-canalicular porosity. This electrical asymmetry engenders a calcium enrichment-exclusion effect that strongly changes the calcium concentration in the lacuno-canalicular fluid and thus modifies the remodelling process. A bibliographic body of evidence supporting this idea is given and its experimental validation is suggested.
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Affiliation(s)
- Thibault Lemaire
- Université Paris Est, Laboratoire Modélisation et Simulation Multi Échelle, MSME UMR CNRS 8208, 61 Avenue du Général de Gaulle, 94010 Créteil, France.
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88
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Wang Z, Yao X, Wang Y. Swelling-induced mesoporous block copolymer membranes with intrinsically active surfaces for size-selective separation. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm34292h] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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89
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Li F, Li L, Liao X, Wang Y. Precise pore size tuning and surface modifications of polymeric membranes using the atomic layer deposition technique. J Memb Sci 2011. [DOI: 10.1016/j.memsci.2011.06.042] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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90
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Chen MY, Klunk MD, Diep VM, Sailor MJ. Electric-field-assisted protein transport, capture, and interferometric sensing in carbonized porous silicon films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:4537-4542. [PMID: 21997305 DOI: 10.1002/adma.201102090] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 07/21/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Michelle Y Chen
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
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91
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Kwak R, Kim SJ, Han J. Continuous-Flow Biomolecule and Cell Concentrator by Ion Concentration Polarization. Anal Chem 2011; 83:7348-55. [DOI: 10.1021/ac2012619] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rhokyun Kwak
- Department of Mechanical Engineering, ‡Department of Electrical Engineering and Computer Science, and §Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Sung Jae Kim
- Department of Mechanical Engineering, ‡Department of Electrical Engineering and Computer Science, and §Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jongyoon Han
- Department of Mechanical Engineering, ‡Department of Electrical Engineering and Computer Science, and §Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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92
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Fine D, Grattoni A, Zabre E, Hussein F, Ferrari M, Liu X. A low-voltage electrokinetic nanochannel drug delivery system. LAB ON A CHIP 2011; 11:2526-34. [PMID: 21677944 DOI: 10.1039/c1lc00001b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Recent work has elucidated the potential of important new therapeutic paradigms, including metronomic delivery and chronotherapy, in which the precise timing and location of therapeutic administration has a significant impact on efficacy and toxicity. New drug delivery architectures are needed to not only release drug continuously at precise rates, but also synchronize their release with circadian cycles. We present an actively controlled nanofluidic membrane that exploits electrophoresis to control the magnitude, duration, and timing of drug release. The membrane, produced using high precision silicon fabrication techniques, has platinum electrodes integrated at the inlet and outlet that allow both amplification and reversal of analyte delivery with low applied voltage (at or below 2 VDC). Device operation was demonstrated with solutions of both fluorescein isothiocyanate conjugated bovine serum albumin and lysozyme using fluorescence spectroscopy, fluorescence microscopy, and a lysozyme specific bio-assay and has been characterized for long-term molecular release and release reversibility. Through a combination of theoretical and experimental analysis, the relative contributions of electrophoresis and electroosmosis have been investigated. The membrane's clinically relevant electrophoretic release rate at 2 VDC exceeds the passive release by nearly one order of magnitude, demonstrating the potential to realize the therapeutic paradigm goal.
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Affiliation(s)
- Daniel Fine
- Department of Nanomedicine, The Methodist Hospital Research Institute, 6670 Bertner Ave, Houston, TX 77030, USA
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93
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Humplik T, Lee J, O'Hern SC, Fellman BA, Baig MA, Hassan SF, Atieh MA, Rahman F, Laoui T, Karnik R, Wang EN. Nanostructured materials for water desalination. NANOTECHNOLOGY 2011; 22:292001. [PMID: 21680966 DOI: 10.1088/0957-4484/22/29/292001] [Citation(s) in RCA: 255] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.
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Affiliation(s)
- T Humplik
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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94
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Spiering A, Getfert S, Sischka A, Reimann P, Anselmetti D. Nanopore translocation dynamics of a single DNA-bound protein. NANO LETTERS 2011; 11:2978-2982. [PMID: 21667921 DOI: 10.1021/nl201541y] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We study the translocation dynamics of a single protein molecule attached to a double-stranded DNA that is threaded through a solid-state nanopore by optical tweezers and an electric field (nanopore force spectroscopy). We find distinct asymmetric and retarded force signals that depend on the protein charge, the DNA elasticity and its counterionic screening in the buffer. A theoretical model where an isolated charge on an elastic, polyelectrolyte strand is experiencing an anharmonic nanopore potential was developed. Its results compare very well with the measured force curves and explain the experimental findings that the force depends linearly on the applied electric field and exhibits a small hysteresis during back and forth translocation cycles. Moreover, the translocation dynamics reflects the stochastic nature of the thermally activated hopping between two adjacent states in the nanopore that can be adequately described by Kramers rate theory.
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Affiliation(s)
- Andre Spiering
- Fakultät für Physik, Universität Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany
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95
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Abstract
At the nanoscale, methods to measure surface charge can prove challenging. Herein we describe a general method to report surface charge through the measurement of ion current rectification of a nanopipette brought in close proximity to a charged substrate. This method is able to discriminate between charged cationic and anionic substrates when the nanopipette is brought within distances from ten to hundreds of nanometers from the surface. Further studies of the pH dependence on the observed rectification support a surface-induced mechanism and demonstrate the ability to further discriminate between cationic and nominally uncharged surfaces. This method could find application in measurement and mapping of heterogeneous surface charges and is particularly attractive for future biological measurements, where noninvasive, noncontact probing of surface charge will prove valuable.
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Affiliation(s)
- Niya Sa
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
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96
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Collier CP, Simpson ML. Micro/nanofabricated environments for synthetic biology. Curr Opin Biotechnol 2011; 22:516-26. [PMID: 21636262 DOI: 10.1016/j.copbio.2011.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 05/06/2011] [Indexed: 11/17/2022]
Abstract
A better understanding of how confinement, crowding and reduced dimensionality modulate reactivity and reaction dynamics will aid in the rational and systematic discovery of functionality in complex biological systems. Artificial microfabricated and nanofabricated structures have helped elucidate the effects of nanoscale spatial confinement and segregation on biological behavior, particularly when integrated with microfluidics, through precise control in both space and time of diffusible signals and binding interactions. Examples of nanostructured interfaces for synthetic biology include the development of cell-like compartments for encapsulating biochemical reactions, nanostructured environments for fundamental studies of diffusion, molecular transport and biochemical reaction kinetics, and regulation of biomolecular interactions as functions of microfabricated and nanofabricated topological constraints.
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Affiliation(s)
- C Patrick Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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97
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Zheng Q, Wei GW. Poisson-Boltzmann-Nernst-Planck model. J Chem Phys 2011; 134:194101. [PMID: 21599038 PMCID: PMC3122111 DOI: 10.1063/1.3581031] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 03/31/2011] [Indexed: 01/23/2023] Open
Abstract
The Poisson-Nernst-Planck (PNP) model is based on a mean-field approximation of ion interactions and continuum descriptions of concentration and electrostatic potential. It provides qualitative explanation and increasingly quantitative predictions of experimental measurements for the ion transport problems in many areas such as semiconductor devices, nanofluidic systems, and biological systems, despite many limitations. While the PNP model gives a good prediction of the ion transport phenomenon for chemical, physical, and biological systems, the number of equations to be solved and the number of diffusion coefficient profiles to be determined for the calculation directly depend on the number of ion species in the system, since each ion species corresponds to one Nernst-Planck equation and one position-dependent diffusion coefficient profile. In a complex system with multiple ion species, the PNP can be computationally expensive and parameter demanding, as experimental measurements of diffusion coefficient profiles are generally quite limited for most confined regions such as ion channels, nanostructures and nanopores. We propose an alternative model to reduce number of Nernst-Planck equations to be solved in complex chemical and biological systems with multiple ion species by substituting Nernst-Planck equations with Boltzmann distributions of ion concentrations. As such, we solve the coupled Poisson-Boltzmann and Nernst-Planck (PBNP) equations, instead of the PNP equations. The proposed PBNP equations are derived from a total energy functional by using the variational principle. We design a number of computational techniques, including the Dirichlet to Neumann mapping, the matched interface and boundary, and relaxation based iterative procedure, to ensure efficient solution of the proposed PBNP equations. Two protein molecules, cytochrome c551 and Gramicidin A, are employed to validate the proposed model under a wide range of bulk ion concentrations and external voltages. Extensive numerical experiments show that there is an excellent consistency between the results predicted from the present PBNP model and those obtained from the PNP model in terms of the electrostatic potentials, ion concentration profiles, and current-voltage (I-V) curves. The present PBNP model is further validated by a comparison with experimental measurements of I-V curves under various ion bulk concentrations. Numerical experiments indicate that the proposed PBNP model is more efficient than the original PNP model in terms of simulation time.
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Affiliation(s)
- Qiong Zheng
- Department of Mathematics, Michigan State University, East Lansing, Michigan 48824, USA
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98
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Nikolaev A, Gracheva ME. Simulation of ionic current through the nanopore in a double-layered semiconductor membrane. NANOTECHNOLOGY 2011; 22:165202. [PMID: 21393823 DOI: 10.1088/0957-4484/22/16/165202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We study the effects of different nanopore geometries (double-conical, single-conical, cylindrical) on the electrostatic potential distribution and ionic conductivity in a double-layered semiconductor nanopore device as functions of the applied membrane bias. Ionic current-voltage characteristics as well as their rectification ratios are calculated using a simple ion transport model. Based on our calculations, we find that the double-layered semiconductor membrane with a single-conical nanopore with a narrow opening in the n-Si layer exhibits the largest range of available potential variations in the pore and, thus, may be better suited for control of polymer translocation through the nanopore.
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Affiliation(s)
- Alexey Nikolaev
- Department of Physics, Clarkson University, Potsdam, NY 13699, USA
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99
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Biotechnical and other applications of nanoporous membranes. Trends Biotechnol 2011; 29:259-66. [PMID: 21388697 DOI: 10.1016/j.tibtech.2011.02.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 01/19/2011] [Accepted: 02/01/2011] [Indexed: 11/21/2022]
Abstract
Recent advances mean that arrays of nearly uniform cylindrical, conical and pyramidal shaped pores can be produced in several types of substrates. Surface modification of nanopore surfaces can give unique mass transport characteristics that have recently been explored for biomolecule separation, detection and purification. Recent interest has focused on the use of nanoporous membranes for mass transfer diodes that act analogous to solid-state devices based on electron conduction. Asymmetric pores such as conical pores can show superior performance characteristics compared to traditional cylindrical pores in ion rectification. However, many phenomena for membranes with asymmetric pores still remain to be exploited in biomolecular separation, biosensing, microfluidics, logic gates, and energy harvesting and storage.
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100
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Li ZR, Liu GR, Hadjiconstantinou NG, Han J, Wang JS, Chen YZ. Dispersive transport of biomolecules in periodic energy landscapes with application to nanofilter sieving arrays. Electrophoresis 2011; 32:506-17. [PMID: 21341285 DOI: 10.1002/elps.201000259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present a theoretical model for describing the electric field-driven migration and dispersion of short anisotropic molecules in nanofluidic filter arrays. The model uses macrotransport theory to derive exact integral-form expressions for the effective mobility and diffusivity of Brownian particles moving in an effective one-dimensional energy landscape. The latter is obtained by modeling the anisotropic molecules as point-sized Brownian particles with their orientational degrees of freedom accounted for by an entropy penalty term, and using a systematic projection procedure for reducing the system dimensionality to the device axial dimension. Our analytical results provide guidance for the design and optimization of nanofluidic separation systems without the need for complex numerical simulations. Comparison with numerical solution of the macrotransport equations in the actual, effectively two-dimensional, geometry shows that the one-dimensional model faithfully describes the field- and size-dependences of mobility and diffusivity, with maximum difference on the order of 10% under the experimentally relevant electric fields.
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Affiliation(s)
- Zi Rui Li
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
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