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Research paper thumbnail of Mechanical Adaptations of Epithelial Cells on Various Protruded Convex Geometries

Cells, 2020

The shape of epithelial tissue supports physiological functions of organs such as intestinal vill... more The shape of epithelial tissue supports physiological functions of organs such as intestinal villi and corneal epithelium. Despite the mounting evidence showing the importance of geometry in tissue microenvironments, the current understanding on how it affects biophysical behaviors of cells is still elusive. Here, we cultured cells on various protruded convex structure such as triangle, square, and circle shape fabricated using two-photon laser lithography and quantitatively analyzed individual cells. Morphological data indicates that epithelial cells can sense the sharpness of the corner by showing the characteristic cell alignments, which was caused by actin contractility. Cell area was mainly influenced by surface convexity, and Rho-activation increased cell area on circle shape. Moreover, we found that intermediate filaments, vimentin, and cytokeratin 8/18, play important roles in growth and adaptation of epithelial cells by enhancing expression level on convex structure dependi...

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Research paper thumbnail of Non-lithographic nanofluidic channels with precisely controlled circular cross sections

RSC Advances, 2018

Printing nanochannel arrays with controlled cross section size and shape using near-field electro... more Printing nanochannel arrays with controlled cross section size and shape using near-field electrospinning.

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Research paper thumbnail of Near-Field Electrospinning for Three-Dimensional Stacked Nanoarchitectures with High Aspect Ratios

Nano Letters, 2019

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Research paper thumbnail of Substrate curvature affects the shape, orientation, and polarization of renal epithelial cells

Acta Biomaterialia, 2018

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Research paper thumbnail of Cell migration in microengineered tumor environments

Lab on a Chip, 2017

Recent advances in microengineered cell migration platforms are discussed critically with focus o... more Recent advances in microengineered cell migration platforms are discussed critically with focus on how cell migration is influenced by engineered tumor microenvironments, the medical relevance being to understand how tumor microenvironments may promote or suppress the progression of cancer.

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Research paper thumbnail of Shear of confined perfiuorinated molecules: Effect of side branching

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Research paper thumbnail of Strain Gradient Plasticity Theory

Encyclopedia of Nanotechnology, 2012

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Research paper thumbnail of Spectroscopie Studies of Confined Molecules Under Shear

MRS Proceedings, 1996

ABSTRACTWe introduce two new techniques with the sensitivity to measure spectroscopie properties ... more ABSTRACTWe introduce two new techniques with the sensitivity to measure spectroscopie properties of confined molecules under shear. One concerns rheo-optics of fluids in micron-sized gaps. The experimental approach consists in applying periodic shear motion to fluid films confined between parallel plates separated by controllable film thickness from 0.1 to 100 micrometers. A key aspect is the concurrent ability to perform spectroscopie experiments (infrared or dielectric spectroscopy, or x-ray or neutron spectroscopy) of these fluids during flow.The second technique consists in flow field experiments of polymer adsorption and orientation. The experimental approach is to produce one-directional shear, at rates up to 104 sec−1, past adsorbed polymer layers of thickness less than 0.01 micrometers. The selective augmentation of vibrational modes oriented preferentially along the chain backbone is then used to probe chain orientation in the direction of flow in a laminar flow field.

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Research paper thumbnail of Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels

The Analyst, 2015

We report the surface modification of thermoplastic nanochannels and the evaluation of the surfac... more We report the surface modification of thermoplastic nanochannels and the evaluation of the surface charge density, zeta potential and electroosmotic flow (EOF).

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Research paper thumbnail of Self-Organized Nanostructures

Encyclopedia of Nanotechnology, 2012

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Research paper thumbnail of Self-assembly of Nanostructures

Encyclopedia of Nanotechnology, 2012

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Research paper thumbnail of Electrospun TiO2 nanofiber integrated lab-on-a-disc for ultrasensitive protein detection from whole blood

Lab on a chip, Jan 16, 2014

ELISA-based devices are promising tools for the detection of low abundant proteins in biological ... more ELISA-based devices are promising tools for the detection of low abundant proteins in biological samples. Reductions of the sample volume and assay time as well as full automation are required for their potential use in point-of-care diagnostic applications. Here, we present a highly efficient lab-on-a-disc composed of a TiO2 nanofibrous mat for sensitive detection of serum proteins with a broad dynamic range, with only 10 μL of whole blood within 30 min. The TiO2 nanofibers provide high specific surface area as well as active functional groups to capture large amounts of antibodies on the surface. In addition, the device offers efficient mixing and washing for improving the signal-to-noise ratio, thus enhancing the overall detection sensitivity. We employ the device for the detection of cardiac biomarkers, C-reactive protein (CRP) and cardiac troponin I (cTnI), spiked in phosphate-buffered saline (PBS) as well as in serum or whole blood. The device exhibited a wide dynamic range of...

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Research paper thumbnail of Shear of confined perfluorinated molecules: Effect of side branching

Wear, 1996

To understand the dependence of nanorheology on molecular architecture for perfluorinated molecul... more To understand the dependence of nanorheology on molecular architecture for perfluorinated molecules, studies were performed using two lubricants commonly used in the magnetic storage industry. Experiments mimicked a single asperity by confining liquids to molecular spacings between atomically smooth mica and applying oscillatory shear forces. The force-distance profiles were compared. Large differences were obtained for the linear shear response. The

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Research paper thumbnail of Molecular tribology of lubricants and additives

Tribology International, 1997

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Research paper thumbnail of A Surface Forces Study of DNA Hybridization

Langmuir, 2001

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Research paper thumbnail of Apparent hydrodynamic thickness of densely grafted polymer layers in a theta solvent

Journal of Polymer Science Part B: Polymer Physics, 1997

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Research paper thumbnail of Dielectric response of polymer films confined between mica surfaces

The Journal of Chemical Physics, 1999

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Research paper thumbnail of A surface forces platform for dielectric measurements

The Journal of Chemical Physics, 2003

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Research paper thumbnail of Flexible fabrication and applications of polymer nanochannels and nanoslits

Chemical Society Reviews, 2011

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Research paper thumbnail of Shear of Confined Perfluorinated Molecules

To understand the dependence of nanorheology on molecular architecture for perfluorinated molecul... more To understand the dependence of nanorheology on molecular architecture for perfluorinated molecules, studies were performed using two lubricants commonly used in the magnetic storage industry. Experiments mimicked a single asperity by confining liquids to molecular spacings between atomically smooth mica and applying oscillatory shear forces. The force-distance profiles were compared. Large differences were obtained for the linear shear response. The elastic and dissipative shear moduli of a branched perfluoropolymer (Krytox-AZ) were comparable even at high loads, signifying that the fluid remained fluid-like over experimental frequencies. However, linear perfluoropolymer (Demmim S-20) was easily solidified. The nonlinear responses were also surprising. Previously, we (G. Reiter et al., Science 263 (1994) 1741) reported that the shear-induced transition from an elastic state (at rest) to a dissipative state (during sliding) was discontinuous and hysteric for various hydrocarbon fluids but not for the perfluorinated chain, perfluoroheptaglyme. However, the stick-slip transition was discontinuous, and even more hysteretic for the linear perfluoropolymer (Demnum S-20)

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Research paper thumbnail of Mechanical Adaptations of Epithelial Cells on Various Protruded Convex Geometries

Cells, 2020

The shape of epithelial tissue supports physiological functions of organs such as intestinal vill... more The shape of epithelial tissue supports physiological functions of organs such as intestinal villi and corneal epithelium. Despite the mounting evidence showing the importance of geometry in tissue microenvironments, the current understanding on how it affects biophysical behaviors of cells is still elusive. Here, we cultured cells on various protruded convex structure such as triangle, square, and circle shape fabricated using two-photon laser lithography and quantitatively analyzed individual cells. Morphological data indicates that epithelial cells can sense the sharpness of the corner by showing the characteristic cell alignments, which was caused by actin contractility. Cell area was mainly influenced by surface convexity, and Rho-activation increased cell area on circle shape. Moreover, we found that intermediate filaments, vimentin, and cytokeratin 8/18, play important roles in growth and adaptation of epithelial cells by enhancing expression level on convex structure dependi...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Non-lithographic nanofluidic channels with precisely controlled circular cross sections

RSC Advances, 2018

Printing nanochannel arrays with controlled cross section size and shape using near-field electro... more Printing nanochannel arrays with controlled cross section size and shape using near-field electrospinning.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Near-Field Electrospinning for Three-Dimensional Stacked Nanoarchitectures with High Aspect Ratios

Nano Letters, 2019

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Substrate curvature affects the shape, orientation, and polarization of renal epithelial cells

Acta Biomaterialia, 2018

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Cell migration in microengineered tumor environments

Lab on a Chip, 2017

Recent advances in microengineered cell migration platforms are discussed critically with focus o... more Recent advances in microengineered cell migration platforms are discussed critically with focus on how cell migration is influenced by engineered tumor microenvironments, the medical relevance being to understand how tumor microenvironments may promote or suppress the progression of cancer.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Shear of confined perfiuorinated molecules: Effect of side branching

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Strain Gradient Plasticity Theory

Encyclopedia of Nanotechnology, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Spectroscopie Studies of Confined Molecules Under Shear

MRS Proceedings, 1996

ABSTRACTWe introduce two new techniques with the sensitivity to measure spectroscopie properties ... more ABSTRACTWe introduce two new techniques with the sensitivity to measure spectroscopie properties of confined molecules under shear. One concerns rheo-optics of fluids in micron-sized gaps. The experimental approach consists in applying periodic shear motion to fluid films confined between parallel plates separated by controllable film thickness from 0.1 to 100 micrometers. A key aspect is the concurrent ability to perform spectroscopie experiments (infrared or dielectric spectroscopy, or x-ray or neutron spectroscopy) of these fluids during flow.The second technique consists in flow field experiments of polymer adsorption and orientation. The experimental approach is to produce one-directional shear, at rates up to 104 sec−1, past adsorbed polymer layers of thickness less than 0.01 micrometers. The selective augmentation of vibrational modes oriented preferentially along the chain backbone is then used to probe chain orientation in the direction of flow in a laminar flow field.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels

The Analyst, 2015

We report the surface modification of thermoplastic nanochannels and the evaluation of the surfac... more We report the surface modification of thermoplastic nanochannels and the evaluation of the surface charge density, zeta potential and electroosmotic flow (EOF).

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Self-Organized Nanostructures

Encyclopedia of Nanotechnology, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Self-assembly of Nanostructures

Encyclopedia of Nanotechnology, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Electrospun TiO2 nanofiber integrated lab-on-a-disc for ultrasensitive protein detection from whole blood

Lab on a chip, Jan 16, 2014

ELISA-based devices are promising tools for the detection of low abundant proteins in biological ... more ELISA-based devices are promising tools for the detection of low abundant proteins in biological samples. Reductions of the sample volume and assay time as well as full automation are required for their potential use in point-of-care diagnostic applications. Here, we present a highly efficient lab-on-a-disc composed of a TiO2 nanofibrous mat for sensitive detection of serum proteins with a broad dynamic range, with only 10 μL of whole blood within 30 min. The TiO2 nanofibers provide high specific surface area as well as active functional groups to capture large amounts of antibodies on the surface. In addition, the device offers efficient mixing and washing for improving the signal-to-noise ratio, thus enhancing the overall detection sensitivity. We employ the device for the detection of cardiac biomarkers, C-reactive protein (CRP) and cardiac troponin I (cTnI), spiked in phosphate-buffered saline (PBS) as well as in serum or whole blood. The device exhibited a wide dynamic range of...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Shear of confined perfluorinated molecules: Effect of side branching

Wear, 1996

To understand the dependence of nanorheology on molecular architecture for perfluorinated molecul... more To understand the dependence of nanorheology on molecular architecture for perfluorinated molecules, studies were performed using two lubricants commonly used in the magnetic storage industry. Experiments mimicked a single asperity by confining liquids to molecular spacings between atomically smooth mica and applying oscillatory shear forces. The force-distance profiles were compared. Large differences were obtained for the linear shear response. The

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Molecular tribology of lubricants and additives

Tribology International, 1997

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A Surface Forces Study of DNA Hybridization

Langmuir, 2001

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Apparent hydrodynamic thickness of densely grafted polymer layers in a theta solvent

Journal of Polymer Science Part B: Polymer Physics, 1997

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dielectric response of polymer films confined between mica surfaces

The Journal of Chemical Physics, 1999

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A surface forces platform for dielectric measurements

The Journal of Chemical Physics, 2003

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Flexible fabrication and applications of polymer nanochannels and nanoslits

Chemical Society Reviews, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Shear of Confined Perfluorinated Molecules

To understand the dependence of nanorheology on molecular architecture for perfluorinated molecul... more To understand the dependence of nanorheology on molecular architecture for perfluorinated molecules, studies were performed using two lubricants commonly used in the magnetic storage industry. Experiments mimicked a single asperity by confining liquids to molecular spacings between atomically smooth mica and applying oscillatory shear forces. The force-distance profiles were compared. Large differences were obtained for the linear shear response. The elastic and dissipative shear moduli of a branched perfluoropolymer (Krytox-AZ) were comparable even at high loads, signifying that the fluid remained fluid-like over experimental frequencies. However, linear perfluoropolymer (Demmim S-20) was easily solidified. The nonlinear responses were also surprising. Previously, we (G. Reiter et al., Science 263 (1994) 1741) reported that the shear-induced transition from an elastic state (at rest) to a dissipative state (during sliding) was discontinuous and hysteric for various hydrocarbon fluids but not for the perfluorinated chain, perfluoroheptaglyme. However, the stick-slip transition was discontinuous, and even more hysteretic for the linear perfluoropolymer (Demnum S-20)

Bookmarks Related papers MentionsView impact