The Experts below are selected from a list of 12246 Experts worldwide ranked by ideXlab platform
Zuzanna S Siwy - One of the best experts on this subject based on the ideXlab platform.
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ion current rectification in nanopores and nanotubes with broken symmetry
Advanced Functional Materials, 2006Co-Authors: Zuzanna S SiwyAbstract:This article focuses on ion transport through nanoporous systems with special emphasis on rectification phenomena. The effect of ion-current rectification is observed as asymmetric current–voltage (I–V) curves, with the current recorded for one voltage polarity higher than the current recorded for the same absolute value of voltage of opposite polarity. This diode-like I–V curve indicates that there is a Preferential Direction for ion flow. Experimental evidence that ion-current rectification is inherent to asymmetric, e.g., tapered, nanoporous systems with excess surface charge is provided and discussed. The fabrication and operation of asymmetric polymer nanopores, gold nanotubes, glass nanocapillaries, and silicon nanopores are presented. The possibility of tuning the Direction and extent of rectification is discussed in detail. Theoretical models that have been developed to explain the ion-current rectification effect are also presented.
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ion current rectification in nanopores and nanotubes with broken symmetry
Advanced Functional Materials, 2006Co-Authors: Zuzanna S SiwyAbstract:This article focuses on ion transport through nanoporous systems with special emphasis on rectification phenomena. The effect of ion-current rectification is observed as asymmetric current–voltage (I–V) curves, with the current recorded for one voltage polarity higher than the current recorded for the same absolute value of voltage of opposite polarity. This diode-like I–V curve indicates that there is a Preferential Direction for ion flow. Experimental evidence that ion-current rectification is inherent to asymmetric, e.g., tapered, nanoporous systems with excess surface charge is provided and discussed. The fabrication and operation of asymmetric polymer nanopores, gold nanotubes, glass nanocapillaries, and silicon nanopores are presented. The possibility of tuning the Direction and extent of rectification is discussed in detail. Theoretical models that have been developed to explain the ion-current rectification effect are also presented.
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a nanodevice for rectification and pumping ions
American Journal of Physics, 2004Co-Authors: Zuzanna S Siwy, A FulinskiAbstract:The transport properties of single asymmetric nanopores in polyetheylene terephthalate (PET) are examined. The pores were produced by a track etching technique based on the irradiation of the foils by swift heavy ions and subsequent chemical etching. Electrical conductivity measurements show that the nanopores in PET are cation selective and rectify the current with the Preferential Direction of cation flow from the narrow entrance toward the wide opening of the pore. Moreover, the pore transports potassium ions against the concentration gradient if stimulated by external field fluctuations. We show that the rectifying and pumping effects are based on the ratchet mechanism.
Keita Ito - One of the best experts on this subject based on the ideXlab platform.
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melt electrospinning writing of poly hydroxymethylglycolide co e caprolactone based scaffolds for cardiac tissue engineering
Advanced Healthcare Materials, 2017Co-Authors: Miguel Castilho, Dries A M Feyen, Maria Flandesiparraguirre, Gernot Hochleitner, Jurgen Groll, Pieter A Doevendans, Tina Vermonden, Keita ItoAbstract:Current limitations in cardiac tissue engineering revolve around the inability to fully recapitulate the structural organization and mechanical environment of native cardiac tissue. This study aims at developing organized ultrafine fiber scaffolds with improved biocompatibility and architecture in comparison to the traditional fiber scaffolds obtained by solution electrospinning. This is achieved by combining the additive manufacturing of a hydroxyl-functionalized polyester, (poly(hydroxymethylglycolide-co-e-caprolactone) (pHMGCL), with melt electrospinning writing (MEW). The use of pHMGCL with MEW vastly improves the cellular response to the mechanical anisotropy. Cardiac progenitor cells (CPCs) are able to align more efficiently along the Preferential Direction of the melt electrospun pHMGCL fiber scaffolds in comparison to electrospun poly(e-caprolactone)-based scaffolds. Overall, this study describes for the first time that highly ordered microfiber (4.0–7.0 µm) scaffolds based on pHMGCL can be reproducibly generated with MEW and that these scaffolds can support and guide the growth of CPCs and thereby potentially enhance their therapeutic potential.
Wei Guo - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions.
ACS Nano, 2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the Preferential Direction for proton transport is opposite under the three types of electrokinetic driving force. The Preferential Direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse Direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions
2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the Preferential Direction for proton transport is opposite under the three types of electrokinetic driving force. The Preferential Direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse Direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing
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asymmetric ion transport through ion channel mimetic solid state nanopores
Accounts of Chemical Research, 2013Co-Authors: Wei Guo, Ye Tian, Lei JiangAbstract:Both scientists and engineers are interested in the design andfabrication of synthetic nanofluidic architectures that mimic the gating functions of biological ion channels. The effort to build such structures requires interdisciplinary efforts at the intersection of chemistry, materials science, and nanotechnology. Biological ion channels and synthetic nanofluidic devices have some structural and chemical similarities, and therefore, they share some common features in regulating the traverse ionic flow. In the past decade, researchers have identified two asymmetric ion transport phenomena in synthetic nanofluidic structures, the rectified ionic current and the net diffusion current. The rectified ionic current is a diode-like current–voltage response that occurs when switching the voltage bias. This phenomenon indicates a Preferential Direction of transport in the nanofluidic system. The net diffusion current occurs as a direct product of charge selectivity and is generated from the asymmetric diffusion t...
Miguel Castilho - One of the best experts on this subject based on the ideXlab platform.
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melt electrospinning writing of poly hydroxymethylglycolide co e caprolactone based scaffolds for cardiac tissue engineering
Advanced Healthcare Materials, 2017Co-Authors: Miguel Castilho, Dries A M Feyen, Maria Flandesiparraguirre, Gernot Hochleitner, Jurgen Groll, Pieter A Doevendans, Tina Vermonden, Keita ItoAbstract:Current limitations in cardiac tissue engineering revolve around the inability to fully recapitulate the structural organization and mechanical environment of native cardiac tissue. This study aims at developing organized ultrafine fiber scaffolds with improved biocompatibility and architecture in comparison to the traditional fiber scaffolds obtained by solution electrospinning. This is achieved by combining the additive manufacturing of a hydroxyl-functionalized polyester, (poly(hydroxymethylglycolide-co-e-caprolactone) (pHMGCL), with melt electrospinning writing (MEW). The use of pHMGCL with MEW vastly improves the cellular response to the mechanical anisotropy. Cardiac progenitor cells (CPCs) are able to align more efficiently along the Preferential Direction of the melt electrospun pHMGCL fiber scaffolds in comparison to electrospun poly(e-caprolactone)-based scaffolds. Overall, this study describes for the first time that highly ordered microfiber (4.0–7.0 µm) scaffolds based on pHMGCL can be reproducibly generated with MEW and that these scaffolds can support and guide the growth of CPCs and thereby potentially enhance their therapeutic potential.
Lei Jiang - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions.
ACS Nano, 2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the Preferential Direction for proton transport is opposite under the three types of electrokinetic driving force. The Preferential Direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse Direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions
2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the Preferential Direction for proton transport is opposite under the three types of electrokinetic driving force. The Preferential Direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse Direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing
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asymmetric ion transport through ion channel mimetic solid state nanopores
Accounts of Chemical Research, 2013Co-Authors: Wei Guo, Ye Tian, Lei JiangAbstract:Both scientists and engineers are interested in the design andfabrication of synthetic nanofluidic architectures that mimic the gating functions of biological ion channels. The effort to build such structures requires interdisciplinary efforts at the intersection of chemistry, materials science, and nanotechnology. Biological ion channels and synthetic nanofluidic devices have some structural and chemical similarities, and therefore, they share some common features in regulating the traverse ionic flow. In the past decade, researchers have identified two asymmetric ion transport phenomena in synthetic nanofluidic structures, the rectified ionic current and the net diffusion current. The rectified ionic current is a diode-like current–voltage response that occurs when switching the voltage bias. This phenomenon indicates a Preferential Direction of transport in the nanofluidic system. The net diffusion current occurs as a direct product of charge selectivity and is generated from the asymmetric diffusion t...
