The Experts below are selected from a list of 19899 Experts worldwide ranked by ideXlab platform
Amit Meller - One of the best experts on this subject based on the ideXlab platform.
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optical recognition of converted dna nucleotides for single molecule dna sequencing using Nanopore arrays
Nano Letters, 2010Co-Authors: Ben Mcnally, Alon Singer, Zhiliang Yu, Zhiping Weng, Amit MellerAbstract:We demonstrate the feasibility of a Nanopore based single-molecule DNA sequencing method, which employs multicolor readout. Target DNA is converted according to a binary code, which is recognized by molecular beacons with two types of fluorophores. Solid-state Nanopores are then used to sequentially strip off the beacons, leading to a series of detectable photon bursts, at high speed. We show that signals from multiple Nanopores can be detected simultaneously, allowing straightforward parallelization to large Nanopore arrays.
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progress toward ultrafast dna sequencing using solid state Nanopores
Clinical Chemistry, 2007Co-Authors: Gautam V Soni, Amit MellerAbstract:Background: Measurements of the ionic current flowing through nanometer-scale pores (Nanopores) have been used to analyze single DNA and RNA molecules, with the ultimate goal of achieving ultrafast DNA sequencing. However, attempts at purely electronic measurements have not achieved the signal contrast required for single nucleotide differentiation. In this report we propose a novel method of optical detection of DNA sequence translocating through a Nanopore. Methods: Each base of the target DNA sequence is 1st mapped onto a 2-unit code, 2 10-bp nucleotide sequence, by biochemical conversion into Designed DNA Polymers. These 2-unit codes are then hybridized to complementary, fluorescently labeled, and self-quenching molecular beacons. As the molecular beacons are sequentially unzipped during translocation through a <2-nm-wide Nanopore, their fluorescent tags are unquenched and are detected by a custom-built dual-color total internal reflection fluorescence (TIRF) microscope. The 2-color optical signal is then correlated to the target DNA sequence. Results: A dual-color TIRFM microscope with single-molecule resolution was constructed, and controlled fabrication of 1-dimensional and 2-dimensional arrays of solid-state Nanopores was performed. A nanofluidic cell assembly was constructed for TIRF-based optical detection of voltage-driven DNA translocation through a Nanopore. Conclusions: We present a novel Nanopore-based DNA sequencing technique that uses an optical readout of DNA translocating unzipping through a Nanopore. Our technique offers better single nucleotide differentiation in sequence readout, as well as the possibility of large-scale parallelism using Nanopore arrays.
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Chemically modified solid-state Nanopores.
Nano letters, 2007Co-Authors: Meni Wanunu, Amit MellerAbstract:Nanopores are extremely sensitive single-molecule sensors. Recently, electron beams have been used to fabricate synthetic Nanopores in thin solid-state membranes with subnanometer resolution. Here we report a new class of chemically modified Nanopore sensors. We describe two approaches for monolayer coating of Nanopores: (1) self-assembly from solution, in which Nanopores ∼10 nm diameter can be reproducibly coated, and (2) self-assembly under voltage-driven electrolyte flow, in which we are able to coat 5 nm Nanopores. We present an extensive characterization of coated Nanopores, their stability, reactivity, and pH response.
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characteristics of solid state nanometre pores fabricated using a transmission electron microscope
Nanotechnology, 2007Co-Authors: Ben Mcnally, Min Jun Kim, Kazuyoshi Murata, Amit MellerAbstract:Solid-state Nanopores can be used to detect nucleic acid structures at the single molecule level. An e-beam has been used to fabricate Nanopores in silicon nitride and silicon dioxide membranes, but the pore formation kinetics, and hence its final structure, remain poorly understood. With the aid of high-resolution TEM imaging as well as TEM tomography we examine the effect of Si3N4 material properties on the Nanopore structure. In particular, we study the dependence of membrane thickness on the Nanopore contraction rate for different initial pore sizes. We explain Nanopore formation kinetics as a balance of two opposite processes: (a) material sputtering and (b) surface-tension-induced shrinking.
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rapid fabrication of uniformly sized Nanopores and Nanopore arrays for parallel dna analysis
Advanced Materials, 2006Co-Authors: Min Jun Kim, Meni Wanunu, David C. Bell, Amit MellerAbstract:Nanometer-sized pores can be used to detect and characterize biopolymers, such as DNA, RNA, and polypeptides, with single-molecule resolution. Experiments performed with the 1.5 nm pore a-hemolysin (a-HL) demonstrated that singlestranded DNA and RNA molecules can be electrophoretically threaded through a pore, and that the ion current flowing through the pore contains information about the biopolymer sequence: its type, length, and secondary structure. The a-HL Nanopore has been used to study the unzipping kinetics of DNA hairpin molecules under stationary or time-varying forces, to detect DNA hybridization kinetics, and to study the interaction of DNA with bound proteins using Nanopore force spectroscopy. In addition, a-HL can be biochemically modified for various sensing tasks, such as analyte detection and ligand–receptor interactions. Solid-state Nanopores can be fabricated in thin Si3N4 and SiO2 membranes, using either an Ar beam or an electron beam (e-beam) in a transmission electron microscope (TEM), as well as in a variety of materials using other techniques. Solid-state Nanopores offer several advantages over phospholipid-embedded protein channels, namely, their size can be tuned with nanometer precision and they exhibit an increased mechanical, chemical, and electrical stability. Recent studies using solid-state pores have begun to emerge, demonstrating the detection of single-stranded and double-stranded DNA molecules. A major advantage of solid-state Nanopores is that they can, in principle, be integrated into devices compatible with other detection schemes in addition to ion current measurements. In particular, optical-based methods offer straightforward parallelism through the simultaneous probing of many Nanopores. Optical methods for sensing single molecules can be implemented by labeling the biomolecules and/or the Nanopores. Although protein pores embedded in a phospholipid bilayer can be interrogated optically to detect single molecules, a stable, long-timescale probing is very complicated since the pores readily diffuse in the bilayer, leading to aggregation and destabilization of the membrane. In contrast, Nanopores fabricated in solid-state materials are static, and are therefore more compatible with optical probing. In this paper, we extend state-of-the-art techniques by demonstrating the rapid fabrication of finely tuned Nanopores and Nanopore arrays. The Nanopores were fabricated in thin Si3N4 films using the intense e-beam of a field-emission TEM. By maximizing the e-beam density at the specimen we achieved a nearly fivefold decrease in the fabrication time of a single Nanopore (ca. 30 s). Investigation of pore contraction/expansion dynamics under different irradiation conditions enabled Nanopore fabrication in the range of 2–20 nm with exceptional size control (<0.5 nm variability). Since the Nanopores were fabricated sequentially (i.e., using one e-beam), both the reduction in fabrication time and size control were crucial for the manufacturing of Nanopore arrays. The 3D Nanopore shape was extensively characterized by performing TEM tomography, as well as by ion-current measurements through the pores. Finally, the detection of double-stranded DNA molecules through 4 nm diameter Nanopores was demonstrated by monitoring their translocation under an applied bias. The starting materials for TEM processing were either fabricated in house or by Protochips Inc. (Raleigh, NC), using the following procedure: low-pressure chemical vapor deposition (LPCVD) was used to form a Si3N4 film (20 or 50 nm thick) on one side of a 500 lm thick Si wafer. A 100 lm× 100 lm window was then fabricated in the wafer using photolithography and standard wet-etching. Nanopore fabrication was then carried out in the thin Si3N4 membrane using a JEOL 2010F field-emission TEM. Alignment of the e-beam involved the adjustment of the condenser stigmatism to the familiar triangle-shaped beam, using a large condenser aperture. The resulting electron-energy-density distribution displayed a threefold aberration. The condenser lens was then used to fully converge the beam to an intense point with a triangular halo of low intensity. The column was then aligned using standard high-resolution transmission electron microscopy alignment procedures. After the alignment procedure, Nanopores with diameters (d) in a range from 3 to 6 nm were directly drilled using an e-beam intensity of ca. 2.5× 10 e nm and a CO M M U N CA IO N
Michael S Strano - One of the best experts on this subject based on the ideXlab platform.
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predicting gas separation through graphene Nanopore ensembles with realistic pore size distributions
ACS Nano, 2021Co-Authors: Zhe Yuan, Ananth Govind Rajan, Michael S Strano, Rahul Prasanna Misra, Daniel BlankschteinAbstract:The development of nanoporous single-layer graphene membranes for gas separation has prompted increasing theoretical investigations of gas transport through graphene Nanopores. However, computer simulations and theories that predict gas permeances through individual graphene Nanopores are not suitable to describe experimental results, because a realistic graphene membrane contains a large number of Nanopores of diverse sizes and shapes. With this need in mind, here, we generate Nanopore ensembles in silico by etching carbon atoms away from pristine graphene with different etching times, using a kinetic Monte Carlo algorithm developed by our group for the isomer cataloging problem of graphene Nanopores. The permeances of H2, CO2, and CH4 through each Nanopore in the ensembles are predicted using transition state theory based on classical all-atomistic force fields. Our findings show that the total gas permeance through a Nanopore ensemble is dominated by a small fraction of large Nanopores with low energy barriers of pore crossing. We also quantitatively predict the increase of the gas permeances and the decrease of the selectivities between the gases as functions of the etching time of graphene. Furthermore, by fitting the theoretically predicted selectivities to the experimental ones reported in the literature, we show that Nanopores in graphene effectively expand as the temperature of permeation measurement increases. We propose that this Nanopore "expansion" is due to the desorption of contaminants that partially clog the graphene Nanopores. In general, our study highlights the effects of the pore size and shape distributions of a graphene Nanopore ensemble on its gas separation properties and calls into attention the potential effect of pore-clogging contamination in experiments.
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addressing the isomer cataloguing problem for Nanopores in two dimensional materials
Nature Materials, 2019Co-Authors: Kevin S Silmore, Jacob Swett, Alex W Robertson, Jamie H Warner, Daniel Blankschtein, Michael S Strano, Ananth Govind RajanAbstract:The presence of extended defects or Nanopores in two-dimensional (2D) materials can change the electronic, magnetic and barrier membrane properties of the materials. However, the large number of possible lattice isomers of Nanopores makes their quantitative study a seemingly intractable problem, confounding the interpretation of experimental and simulated data. Here we formulate a solution to this isomer cataloguing problem (ICP), combining electronic-structure calculations, kinetic Monte Carlo simulations, and chemical graph theory, to generate a catalogue of unique, most-probable isomers of 2D lattice Nanopores. The results demonstrate remarkable agreement with precise Nanopore shapes observed experimentally in graphene and show that the thermodynamic stability of a Nanopore is distinct from its kinetic stability. Triangular Nanopores prevalent in hexagonal boron nitride are also predicted, extending this approach to other 2D lattices. The proposed method should accelerate the application of nanoporous 2D materials by establishing specific links between experiment and theory/simulations, and by providing a much-needed connection between molecular design and fabrication. Nanopores in 2D materials have various possible lattice isomers, making relevant quantitative analysis difficult. An isomer-cataloguing framework is developed to address this problem, demonstrating remarkable agreement between simulated and experimental data.
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addressing the isomer cataloguing problem for Nanopores in two dimensional materials
Nature Materials, 2019Co-Authors: Ananth Govind Rajan, Kevin S Silmore, Jacob Swett, Alex W Robertson, Jamie H Warner, Daniel Blankschtein, Michael S StranoAbstract:The presence of extended defects or Nanopores in two-dimensional (2D) materials can change the electronic, magnetic and barrier membrane properties of the materials. However, the large number of possible lattice isomers of Nanopores makes their quantitative study a seemingly intractable problem, confounding the interpretation of experimental and simulated data. Here we formulate a solution to this isomer cataloguing problem (ICP), combining electronic-structure calculations, kinetic Monte Carlo simulations, and chemical graph theory, to generate a catalogue of unique, most-probable isomers of 2D lattice Nanopores. The results demonstrate remarkable agreement with precise Nanopore shapes observed experimentally in graphene and show that the thermodynamic stability of a Nanopore is distinct from its kinetic stability. Triangular Nanopores prevalent in hexagonal boron nitride are also predicted, extending this approach to other 2D lattices. The proposed method should accelerate the application of nanoporous 2D materials by establishing specific links between experiment and theory/simulations, and by providing a much-needed connection between molecular design and fabrication.
Sebastien Balme - One of the best experts on this subject based on the ideXlab platform.
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amyloid growth inhibition and real time enzymatic degradation revealed with single conical Nanopore
Analytical Chemistry, 2018Co-Authors: Nicoletta Giamblanco, Emmanuel Balanzat, Jean-marc Janot, Diego Coglitore, Alberto Gubbiotti, Mauro Chinappi, Sebastien BalmeAbstract:Amyloid fibrils are involved in several neurodegenerative diseases. However, because of their polymorphism and low concentration, they are challenging to assess in real-time with conventional techniques. Here, we present a new approach for the characterization of the intermediates: protofibrils and “end-off” aggregates which are produced during the amyloid formation. To do so, we have fashioned conical track-etched Nanopores that are functionalized to prevent the fouling. Using these Nanopores, we have followed the kinetic of amyloid growth to discriminate the different intermediates protofibrils and “end-off. Then, the Nanopore was used to characterize the effect of promoter and inhibitor of the fibrillation process. Finally, we have followed in real-time the degradation of amyloid with peptase. Compare with the SiN Nanopore, the track-etched one features exceptionally high success rate via functionalization and detection in “one-pot”. Our results demonstrate the potential for a conical Nanopore to be us...
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ionic transport through sub 10 nm diameter hydrophobic high aspect ratio Nanopores experiment theory and simulation
Scientific Reports, 2015Co-Authors: Sebastien Balme, Simon Cabelloaguilar, Mikhael Bechelany, Fabien Picaud, Emmanuel Balanzat, Philippe Miele, Manoel Manghi, John Palmeri, Adib Abouchaaya, Jean-marc JanotAbstract:Fundamental understanding of ionic transport at the nanoscale is essential for developing biosensors based on Nanopore technology and new generation high-performance nanofiltration membranes for separation and purification applications. We study here ionic transport through single putatively neutral hydrophobic Nanopores with high aspect ratio (of length L = 6 μm with diameters ranging from 1 to 10 nm) and with a well controlled cylindrical geometry. We develop a detailed hybrid mesoscopic theoretical approach for the electrolyte conductivity inside Nanopores, which considers explicitly ion advection by electro-osmotic flow and possible flow slip at the pore surface. By fitting the experimental conductance data we show that for Nanopore diameters greater than 4 nm a constant weak surface charge density of about 10−2 C m−2 needs to be incorporated in the model to account for conductance plateaus of a few pico-siemens at low salt concentrations. For tighter Nanopores, our analysis leads to a higher surface charge density, which can be attributed to a modification of ion solvation structure close to the pore surface, as observed in the molecular dynamics simulations we performed.
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combining a sensor and a ph gated Nanopore based on an avidin biotin system
Chemical Communications, 2015Co-Authors: Mathilde Lepoitevin, Mikhael Bechelany, Emmanuel Balanzat, Jean-marc Janot, Gael Nguyen, Sebastien BalmeAbstract:Here we propose a new approach to tailor Nanopores, which combines both pH gating and sensing properties. This strategy is based on PEG like-avidin grafting in Nanopores designed by atomic layer deposition (ALD). Below pH 5 the Nanopore is blocked. We show that the PEG chains are at the origin of these properties.
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dynamics of polymer nanoparticles through a single artificial Nanopore with a high aspect ratio
Soft Matter, 2014Co-Authors: Simon Cabelloaguilar, Adib Abou Chaaya, Mikhael Bechelany, Emmanuel Balanzat, Jean-marc Janot, Celine Pochatbohatier, Philippe Miele, Sebastien BalmeAbstract:The development of nanometric Coulter counters for nanoparticle detection is an attractive and promising field of research. In this work, we have studied the influence of the Nanopore surface state on charged polymer nanoparticle translocations. To make this, the translocation of carboxylate modified polystyrene microspheres (diameter 40, 70 and 100 nm) has been investigated through two kinds of high aspect ratio Nanopores (negative and uncharged). The latter were tailored by a single track-etched and atomic layer deposition technique. It was shown that the mobility and the energy barrier are strongly dependent on Nanopore surface charge. Typically if the latter exhibits negative surface charge, the microsphere mobility increases and the global energy barrier of entrance inside the Nanopore decreases with its diameter, converse to the uncharged Nanopore.
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ionic selectivity of nystatin a1 confined in nanoporous track etched polymer membrane
Iet Nanobiotechnology, 2014Co-Authors: Sebastien Balme, Sebastian Kraszewski, Fabien Picaud, Jean-marc Janot, Daniela Thiele, Philippe DejardinAbstract:The hybrid biological/polymeric solid-state Nanopore membrane offers several opportunities to combine the advantage of biological channel (selectivity) and material (robustness). Based on this technology, the challenge is to obtain selective ionic exchange membranes, with no energy intake. The direct insertion of an ionic channel inside a Nanopore should be a promise solution. Here, the authors report a hybrid Nanopore based on nystatin A1 confinement in commercial Nanopore membrane. Ionic transport and selectivity studies show that the hybrid Nanopores exhibit mainly an anionic behaviour, on the contrary to biological conditions. However, the order of magnitude between the different ratios of permeation of several cationic species is retained even if the blocking of divalent cation is not totally proved.
Ananth Govind Rajan - One of the best experts on this subject based on the ideXlab platform.
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predicting gas separation through graphene Nanopore ensembles with realistic pore size distributions
ACS Nano, 2021Co-Authors: Zhe Yuan, Ananth Govind Rajan, Michael S Strano, Rahul Prasanna Misra, Daniel BlankschteinAbstract:The development of nanoporous single-layer graphene membranes for gas separation has prompted increasing theoretical investigations of gas transport through graphene Nanopores. However, computer simulations and theories that predict gas permeances through individual graphene Nanopores are not suitable to describe experimental results, because a realistic graphene membrane contains a large number of Nanopores of diverse sizes and shapes. With this need in mind, here, we generate Nanopore ensembles in silico by etching carbon atoms away from pristine graphene with different etching times, using a kinetic Monte Carlo algorithm developed by our group for the isomer cataloging problem of graphene Nanopores. The permeances of H2, CO2, and CH4 through each Nanopore in the ensembles are predicted using transition state theory based on classical all-atomistic force fields. Our findings show that the total gas permeance through a Nanopore ensemble is dominated by a small fraction of large Nanopores with low energy barriers of pore crossing. We also quantitatively predict the increase of the gas permeances and the decrease of the selectivities between the gases as functions of the etching time of graphene. Furthermore, by fitting the theoretically predicted selectivities to the experimental ones reported in the literature, we show that Nanopores in graphene effectively expand as the temperature of permeation measurement increases. We propose that this Nanopore "expansion" is due to the desorption of contaminants that partially clog the graphene Nanopores. In general, our study highlights the effects of the pore size and shape distributions of a graphene Nanopore ensemble on its gas separation properties and calls into attention the potential effect of pore-clogging contamination in experiments.
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addressing the isomer cataloguing problem for Nanopores in two dimensional materials
Nature Materials, 2019Co-Authors: Kevin S Silmore, Jacob Swett, Alex W Robertson, Jamie H Warner, Daniel Blankschtein, Michael S Strano, Ananth Govind RajanAbstract:The presence of extended defects or Nanopores in two-dimensional (2D) materials can change the electronic, magnetic and barrier membrane properties of the materials. However, the large number of possible lattice isomers of Nanopores makes their quantitative study a seemingly intractable problem, confounding the interpretation of experimental and simulated data. Here we formulate a solution to this isomer cataloguing problem (ICP), combining electronic-structure calculations, kinetic Monte Carlo simulations, and chemical graph theory, to generate a catalogue of unique, most-probable isomers of 2D lattice Nanopores. The results demonstrate remarkable agreement with precise Nanopore shapes observed experimentally in graphene and show that the thermodynamic stability of a Nanopore is distinct from its kinetic stability. Triangular Nanopores prevalent in hexagonal boron nitride are also predicted, extending this approach to other 2D lattices. The proposed method should accelerate the application of nanoporous 2D materials by establishing specific links between experiment and theory/simulations, and by providing a much-needed connection between molecular design and fabrication. Nanopores in 2D materials have various possible lattice isomers, making relevant quantitative analysis difficult. An isomer-cataloguing framework is developed to address this problem, demonstrating remarkable agreement between simulated and experimental data.
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addressing the isomer cataloguing problem for Nanopores in two dimensional materials
Nature Materials, 2019Co-Authors: Ananth Govind Rajan, Kevin S Silmore, Jacob Swett, Alex W Robertson, Jamie H Warner, Daniel Blankschtein, Michael S StranoAbstract:The presence of extended defects or Nanopores in two-dimensional (2D) materials can change the electronic, magnetic and barrier membrane properties of the materials. However, the large number of possible lattice isomers of Nanopores makes their quantitative study a seemingly intractable problem, confounding the interpretation of experimental and simulated data. Here we formulate a solution to this isomer cataloguing problem (ICP), combining electronic-structure calculations, kinetic Monte Carlo simulations, and chemical graph theory, to generate a catalogue of unique, most-probable isomers of 2D lattice Nanopores. The results demonstrate remarkable agreement with precise Nanopore shapes observed experimentally in graphene and show that the thermodynamic stability of a Nanopore is distinct from its kinetic stability. Triangular Nanopores prevalent in hexagonal boron nitride are also predicted, extending this approach to other 2D lattices. The proposed method should accelerate the application of nanoporous 2D materials by establishing specific links between experiment and theory/simulations, and by providing a much-needed connection between molecular design and fabrication.
Jean-marc Janot - One of the best experts on this subject based on the ideXlab platform.
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amyloid growth inhibition and real time enzymatic degradation revealed with single conical Nanopore
Analytical Chemistry, 2018Co-Authors: Nicoletta Giamblanco, Emmanuel Balanzat, Jean-marc Janot, Diego Coglitore, Alberto Gubbiotti, Mauro Chinappi, Sebastien BalmeAbstract:Amyloid fibrils are involved in several neurodegenerative diseases. However, because of their polymorphism and low concentration, they are challenging to assess in real-time with conventional techniques. Here, we present a new approach for the characterization of the intermediates: protofibrils and “end-off” aggregates which are produced during the amyloid formation. To do so, we have fashioned conical track-etched Nanopores that are functionalized to prevent the fouling. Using these Nanopores, we have followed the kinetic of amyloid growth to discriminate the different intermediates protofibrils and “end-off. Then, the Nanopore was used to characterize the effect of promoter and inhibitor of the fibrillation process. Finally, we have followed in real-time the degradation of amyloid with peptase. Compare with the SiN Nanopore, the track-etched one features exceptionally high success rate via functionalization and detection in “one-pot”. Our results demonstrate the potential for a conical Nanopore to be us...
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ionic transport through sub 10 nm diameter hydrophobic high aspect ratio Nanopores experiment theory and simulation
Scientific Reports, 2015Co-Authors: Sebastien Balme, Simon Cabelloaguilar, Mikhael Bechelany, Fabien Picaud, Emmanuel Balanzat, Philippe Miele, Manoel Manghi, John Palmeri, Adib Abouchaaya, Jean-marc JanotAbstract:Fundamental understanding of ionic transport at the nanoscale is essential for developing biosensors based on Nanopore technology and new generation high-performance nanofiltration membranes for separation and purification applications. We study here ionic transport through single putatively neutral hydrophobic Nanopores with high aspect ratio (of length L = 6 μm with diameters ranging from 1 to 10 nm) and with a well controlled cylindrical geometry. We develop a detailed hybrid mesoscopic theoretical approach for the electrolyte conductivity inside Nanopores, which considers explicitly ion advection by electro-osmotic flow and possible flow slip at the pore surface. By fitting the experimental conductance data we show that for Nanopore diameters greater than 4 nm a constant weak surface charge density of about 10−2 C m−2 needs to be incorporated in the model to account for conductance plateaus of a few pico-siemens at low salt concentrations. For tighter Nanopores, our analysis leads to a higher surface charge density, which can be attributed to a modification of ion solvation structure close to the pore surface, as observed in the molecular dynamics simulations we performed.
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combining a sensor and a ph gated Nanopore based on an avidin biotin system
Chemical Communications, 2015Co-Authors: Mathilde Lepoitevin, Mikhael Bechelany, Emmanuel Balanzat, Jean-marc Janot, Gael Nguyen, Sebastien BalmeAbstract:Here we propose a new approach to tailor Nanopores, which combines both pH gating and sensing properties. This strategy is based on PEG like-avidin grafting in Nanopores designed by atomic layer deposition (ALD). Below pH 5 the Nanopore is blocked. We show that the PEG chains are at the origin of these properties.
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dynamics of polymer nanoparticles through a single artificial Nanopore with a high aspect ratio
Soft Matter, 2014Co-Authors: Simon Cabelloaguilar, Adib Abou Chaaya, Mikhael Bechelany, Emmanuel Balanzat, Jean-marc Janot, Celine Pochatbohatier, Philippe Miele, Sebastien BalmeAbstract:The development of nanometric Coulter counters for nanoparticle detection is an attractive and promising field of research. In this work, we have studied the influence of the Nanopore surface state on charged polymer nanoparticle translocations. To make this, the translocation of carboxylate modified polystyrene microspheres (diameter 40, 70 and 100 nm) has been investigated through two kinds of high aspect ratio Nanopores (negative and uncharged). The latter were tailored by a single track-etched and atomic layer deposition technique. It was shown that the mobility and the energy barrier are strongly dependent on Nanopore surface charge. Typically if the latter exhibits negative surface charge, the microsphere mobility increases and the global energy barrier of entrance inside the Nanopore decreases with its diameter, converse to the uncharged Nanopore.
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ionic selectivity of nystatin a1 confined in nanoporous track etched polymer membrane
Iet Nanobiotechnology, 2014Co-Authors: Sebastien Balme, Sebastian Kraszewski, Fabien Picaud, Jean-marc Janot, Daniela Thiele, Philippe DejardinAbstract:The hybrid biological/polymeric solid-state Nanopore membrane offers several opportunities to combine the advantage of biological channel (selectivity) and material (robustness). Based on this technology, the challenge is to obtain selective ionic exchange membranes, with no energy intake. The direct insertion of an ionic channel inside a Nanopore should be a promise solution. Here, the authors report a hybrid Nanopore based on nystatin A1 confinement in commercial Nanopore membrane. Ionic transport and selectivity studies show that the hybrid Nanopores exhibit mainly an anionic behaviour, on the contrary to biological conditions. However, the order of magnitude between the different ratios of permeation of several cationic species is retained even if the blocking of divalent cation is not totally proved.
