The Experts below are selected from a list of 311058 Experts worldwide ranked by ideXlab platform
Ruben Perez - One of the best experts on this subject based on the ideXlab platform.
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dynamic Atomic Force Microscopy methods
Surface Science Reports, 2002Co-Authors: Ricardo Garcia, Ruben PerezAbstract:Abstract In this report we review the fundamentals, applications and future tendencies of dynamic Atomic Force Microscopy (AFM) methods. Our focus is on understanding why the changes observed in the dynamic properties of a vibrating tip that interacts with a surface make possible to obtain molecular resolution images of membrane proteins in aqueous solutions or to resolve Atomic-scale surface defects in ultra high vacuum (UHV). Our description of the two major dynamic AFM modes, amplitude modulation Atomic Force Microscopy (AM-AFM) and frequency modulation Atomic Force Microscopy (FM-AFM) emphasises their common points without ignoring the differences in experimental set-ups and operating conditions. Those differences are introduced by the different feedback parameters, oscillation amplitude in AM-AFM and frequency shift and excitation amplitude in FM-AFM, used to track the topography and composition of a surface. The theoretical analysis of AM-AFM (also known as tapping-mode) emphasises the coexistence, in many situations of interests, of two stable oscillation states, a low and high amplitude solution. The coexistence of those oscillation states is a consequence of the presence of attractive and repulsive components in the interaction Force and their non-linear dependence on the tip–surface separation. We show that key relevant experimental properties such as the lateral resolution, image contrast and sample deformation are highly dependent on the oscillation state chosen to operate the instrument. AM-AFM allows to obtain simultaneous topographic and compositional contrast in heterogeneous samples by recording the phase angle difference between the external excitation and the tip motion (phase imaging). Significant applications of AM-AFM such as high-resolution imaging of biomolecules and polymers, large-scale patterning of silicon surfaces, manipulation of single nanoparticles or the fabrication of single electron devices are also reviewed. FM-AFM (also called non-contact AFM—NC-AFM) has achieved the long-standing goal of true Atomic resolution with AFM in UHV. Our analysis starts with a discussion of the relation between frequency shifts and tip–surface interactions, emphasising the ability of perturbation theory to describe the measured frequency shift. We discuss the role of short-range chemical interactions in the Atomic contrast, with particular attention to semiconductor and ionic (alkali halides and oxides) surfaces. Also included is a detailed quantitative comparison between theoretical simulations and experiment. Inversion procedures, the determination of the tip–sample interaction from the frequency shift versus distance curves above specific sites, are also reviewed. We finish with a discussion of the optimal range of experimental operation parameters, and the use of damping (excitation amplitude) as a source of Atomic contrast, including the possible interpretation in terms of microscopic dissipation mechanisms.
Zhifeng Shao - One of the best experts on this subject based on the ideXlab platform.
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Probing Nanometer Structures with Atomic Force Microscopy.
Physiology, 1999Co-Authors: Zhifeng ShaoAbstract:Atomic Force Microscopy (AFM) can generate high-resolution images of the surface of biological specimens and can also probe the interactions between and within single macromolecules. Thus isolated heterogeneous biological structures can be studied in submolecular detail with AFM.
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RECENT ADVANCES IN BIOLOGICAL Atomic Force Microscopy
Micron, 1995Co-Authors: Jie Yang, Zhifeng ShaoAbstract:Recent developments in biological Atomic Force Microscopy are reviewed. In addition to the advances in methodology, new structural information of different biological systems revealed by the Atomic Force Microscopy is also presented. A discussion regarding the contrast, resolution and specimen deformation is provided based on a theoretical model.
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Promises and problems of biological Atomic Force Microscopy
Journal of Microscopy, 1993Co-Authors: Jie Yang, L. K. Tamm, Andrew P. Somlyo, Zhifeng ShaoAbstract:Summary Recent developments in the biological applications of Atomic Force Microscopy are reviewed, and the great potential of this novel, high-resolution imaging technique, including its limitations and possible future directions for biological research, are discussed.
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Atomic Force Microscopy of DNA molecules
FEBS Letters, 1992Co-Authors: Jie Yang, Kunio Takeyasu, Zhifeng ShaoAbstract:DNA-cytochrome complexes adsorbed on carbon-coated micasurfaces were directly imaged by Atomic Force Microscopy in air using commercially available cantilevers, with a routine resolution of 6 nm. Images of M13 phage DNA and M13-DNA polymerase complex are also shown. © 1992.
Toshihiro Tsuji - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Materials - Ultrasonic Atomic Force Microscopy
Characterization of Materials, 2012Co-Authors: Kazushi Yamanaka, Toshihiro TsujiAbstract:For the development of advanced electronic and mechanical devices on the micro- and nanoscale, there is an increasing need for the characterization of elasticity and subsurface defects. As a useful method, principle, implementation, and applications of ultrasonic Atomic Force Microscopy (UAFM) and related methods for elastic materials characterization are described. It measures the contact stiffness from the resonance frequency of cantilever with the tip in contact with the sample surface. We focus on the concept of effective enhancement of the cantilever stiffness caused by the inertia of a soft cantilever at or above the contact resonance frequency. By virtue of this effect, new findings on elasticity of materials were achieved by many groups so far. Relation between UAFM and ordinary Atomic Force Microscopy (AFM) is explained in detail. Also, lateral modulation Atomic Force Microscopy (LM-AFM) with application to nanotribology is explained. Keywords: Atomic Force Microscopy; nanotechnology; elasticity; ultrasonics; defects; contact resonance; contact stiffness; graphene; delamination
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Ultrasonic Atomic Force Microscopy of Subsurface Defects
Acoustical Imaging, 2008Co-Authors: Kazushi Yamanaka, Kentaro Kobari, S. Ide, Toshihiro TsujiAbstract:We show principle, implementation and remarkable applications of ultrasonic Atomic Force Microscopy (UAFM) to evaluation of components with scientific and technological importance. In particular, carbon fiber in CFRP, domain of ferroelectric PZT and subsurface delamination of electrodes in microdevices are shown. We also show lateral modulation Atomic Force Microscopy (LM-AFM) with application to a carbon nanotube composite and discuss its extension using combination with UAFM.
Christopher Hall - One of the best experts on this subject based on the ideXlab platform.
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direct measurement of salt mineral repulsion using Atomic Force Microscopy
Chemical Communications, 2010Co-Authors: Andrea Hamilton, Vasileios Koutsos, Christopher HallAbstract:The disjoining pressure between a mineral and soluble salt crystal in concentrated aqueous solution has been successfully measured with Atomic Force Microscopy.
Daniel J Muller - One of the best experts on this subject based on the ideXlab platform.
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Atomic Force Microscopy-based mechanobiology
Nature Reviews Physics, 2019Co-Authors: Michael Krieg, Gotthold Fläschner, Benjamin M. Gaub, Wouter H Roos, Hermann E Gaub, David Alsteens, Yves F Dufrene, Gijs J L Wuite, Christoph Gerber, Daniel J MullerAbstract:Mechanobiology describes how biological systems respond to mechanical stimuli. This Review surveys basic principles, advantages and limitations of applying and combining Atomic Force Microscopy-based modalities with complementary techniques to characterize the morphology, mechanical properties and functional response of complex biological systems to mechanical cues.Key pointsThe versatile functions of biological systems ranging from molecules, cells and cellular systems to living organisms are governed by their mechanical properties and ability to sense mechanical cues and respond to them. Atomic Force Microscopy (AFM)-based approaches provide multifunctional nanotools to measure a wide variety of mechanical properties of living systems and to apply to them well-defined mechanical cues. AFM allows us to apply and measure Forces from the piconewton to the micronewton range on spatially defined areas with sizes ranging from the sub-nanometre to several tens of micrometres. Mechanical parameters characterized by AFM include Force, pressure, tension, adhesion, friction, elasticity, viscosity and energy dissipation. The mechanical parameters of complex biological systems can be structurally mapped, with a spatial resolution ranging from millimetres to sub-nanometres and at kinetic ranges from hours to milliseconds. AFM can be combined with various complementary methods to characterize a multitude of mechanical, functional and morphological properties and responses of complex biological systems.AbstractMechanobiology emerges at the crossroads of medicine, biology, biophysics and engineering and describes how the responses of proteins, cells, tissues and organs to mechanical cues contribute to development, differentiation, physiology and disease. The grand challenge in mechanobiology is to quantify how biological systems sense, transduce, respond and apply mechanical signals. Over the past three decades, Atomic Force Microscopy (AFM) has emerged as a key platform enabling the simultaneous morphological and mechanical characterization of living biological systems. In this Review, we survey the basic principles, advantages and limitations of the most common AFM modalities used to map the dynamic mechanical properties of complex biological samples to their morphology. We discuss how mechanical properties can be directly linked to function, which has remained a poorly addressed issue. We outline the potential of combining AFM with complementary techniques, including optical Microscopy and spectroscopy of mechanosensitive fluorescent constructs, super-resolution Microscopy, the patch clamp technique and the use of microstructured and fluidic devices to characterize the 3D distribution of mechanical responses within biological systems and to track their morphology and functional state.
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Atomic Force Microscopy based mechanobiology
Nature Reviews Physics, 2019Co-Authors: Michael Krieg, Gotthold Fläschner, Benjamin M. Gaub, Wouter H Roos, Hermann E Gaub, David Alsteens, Yves F Dufrene, Gijs J L Wuite, Christoph Gerber, Daniel J MullerAbstract:Mechanobiology emerges at the crossroads of medicine, biology, biophysics and engineering and describes how the responses of proteins, cells, tissues and organs to mechanical cues contribute to development, differentiation, physiology and disease. The grand challenge in mechanobiology is to quantify how biological systems sense, transduce, respond and apply mechanical signals. Over the past three decades, Atomic Force Microscopy (AFM) has emerged as a key platform enabling the simultaneous morphological and mechanical characterization of living biological systems. In this Review, we survey the basic principles, advantages and limitations of the most common AFM modalities used to map the dynamic mechanical properties of complex biological samples to their morphology. We discuss how mechanical properties can be directly linked to function, which has remained a poorly addressed issue. We outline the potential of combining AFM with complementary techniques, including optical Microscopy and spectroscopy of mechanosensitive fluorescent constructs, super-resolution Microscopy, the patch clamp technique and the use of microstructured and fluidic devices to characterize the 3D distribution of mechanical responses within biological systems and to track their morphology and functional state. Mechanobiology describes how biological systems respond to mechanical stimuli. This Review surveys basic principles, advantages and limitations of applying and combining Atomic Force Microscopy-based modalities with complementary techniques to characterize the morphology, mechanical properties and functional response of complex biological systems to mechanical cues.