Diociaiuti M, Bordi F, Motta A, Carosi A, Ercolini E, Arancia G, Cametti C, Coluzza C. Gramicidin A aggregation in phospholipid Langmuir-Blodget monolayers: an atomic force microscopy study. In: 12. European Congress on Electron Microscopy. Proceedings ; July 9-14, 2000; Brno. 2000. p.B535-B536 ...
Park Systems, a leader in Atomic Force Microscopy (AFM) since 1997 announces their first AFM image contest winner, Namuna Panday, a Graduate Student at Florida International University. Her winning submission is an AFM image taken using Park XE Bio of a HeLa Cell used in her research studying drug delivery methods for cancer research.
Atomic force microscopy (AFM) for single-cell force spectroscopy (SCFS) and Poisson statistic were used to analyze the detachment work recorded during the removal of gold-covered microspheres from cardiac fibroblasts. The effect of Cytochalasin D, a disruptor of the actin cytoskeleton, on cell adhesion was also tested. The adhesion workwas assessed using a Poisson analysis also derived fromsingle-cell force spectroscopy retracting curves. The use of Poisson analysis to get adhesionwork fromAFM curves is quite a novel method, and in this case, proved to be effective to study the short-range and long-range contributions to the adhesion work. This method avoids the difficult identification of minor peaks in the AFMretracting curves by creating what can be considered an average adhesionwork. Even though the effect of actin depolymerisation iswell documented, its use revealed that control cardiac fibroblasts (CT) exhibit a work of adhesion at least 5 times higher than that of the Cytochalasin treated ...
In this thesis properties and influence of modification techniques of porous silicon were studied by Atomic Force Microscope (AFM). This device permits to visualize the surface topography and to study properties of the samples on atomic scale, which was necessary for recent investigation. Samples of porous silicon were obtained by electrochemical etching. Nickel particles were deposited by two methods: electrochemical deposition and extracting from NiCl2 ethanol solution. Sample growth was conducted in Saint-Petersburg State Electrotechnical University, LETI ...
From consumer productions to energy production, algae is used in many industrial processes. Understanding the mechanical behavior of algae is important to optimize these processes. To obtain a better understanding of algae cell response, we mechanically characterized single, dried Scenedesmus dimorphus cells. To accomplish this, we used atomic force microscopy (AFM) to image S. dimorphus cells, which enabled us to map the AFM measurements to a location on the individual cells. We were then able to perform force measurements on the AFM to determine the Youngs modulus of S. dimorphus. These findings enable a more detailed understanding of the mechanical properties of a single S. dimorphus cell, which may be useful in many applications.. Copyright © 2013 by ASME ...
Kenta Iwashima, Kenji Watanabe, and Jiro Kumaki. Department of Organic Materials Science, Yamagata University, Japan. Polymer monolayers spread on a water surface transform from an isolated chain to amorphous, then to a crystalline state upon compression, which can be transferred at each stage onto a substrate for observation by atomic force microcopy (AFM) [1]. Previously, we successfully observed a folded chain crystal (FCC) of an isotactic poly(methyl methacrylate) (it-PMMA) [2], its melting behavior in situ at high temperature [3], and crystallization of single isolated chains [4] at a molecular level by AFM.. In contrast to the it-PMMA, polylactide (PLA) crystallizes into an extended chain crystal (ECC) on a water surface [5]. Since the width of the crystal corresponds to the molecular weight (Mw), the chain packing in the crystal can be specifically identified. We studied the crystallization of a mixture of high and low Mw PLAs and found that the high Mw PLA first crystallized, followed by ...
In this thesis methods for investigation of orientation and conformation of individual macromolecules on surfaces are presented as well as novel methods for functionalization of silicon chips with the possibility to get an ordered immobilization of antibodies. Two novel methods are presented which makes it possible to investigate the orientation of individual macromolecules on different kinds of surfaces with AFM. One is based on threshold patterning where, depending on substrate, side- and end-on adsorbed immunoglobulin molecules could be detected. The other method is using the principle of site-specific ligands where the orientation of proteins adsorbed to various surfaces was evaluated. By measuring the increase in protein volume of the formed protein-ligand complexes with AFM, the amount of protein having an orientation that allows binding can be estimated. The influence of surface chemistry on protein structure was examined using human serum fibronectin adsorbed to hydrophilic and ...
Публикации за 2009 год. Strekal, N.; Kulakovich, O.; Askirka, V.; Sveklo, I.; Maskevich, S. Features of the Secondary Emission Enhancement Near Plasmonic Gold Film, - Plasmonics, 2009, Vol. 4, pp. 1-7.. A.V. Belko, A.V. Nikitin, N.D. Strekal, A.E. German. Fractal Structure of Gold Clusters Formed under Vacuum Deposition on Dielectric Substrates // X-ray, Synchrotron and Neutron Techniques, 2009, Vol. 3, No. 3, pp. 338-342.. A Hyper-Raman Spectroscopy, Spectrophotometry and Atomic Force Microscopy Study of Photochromism of Spirocyclic Compounds on Nanostructured Metal Films / G.T. Vasilyuk, S.A. Maskevich, A.E. German, I.F. Sveklo, B.S. Lukyanov, L.A. Ageev. // High Energy Chemistry, 2009,Vol.43, No.7, pp.623-627.. ...
This paper demonstrates an acoustic sensor that can resolve atomic force microscopy (AFM) tip blunting with a frequency sensitivity of 0.007%. The AFM tip is fabricated on a thin film piezoelectric aluminum nitride (AlN) membrane that is excited as a film bulk acoustic resonator (FBAR). We demonstrate that cutting 0.98 μm off of the tip apex results in a resonance frequency change of 0.4MHz at 6.387GHz. This work demonstrates the potential for in-situ monitoring of AFM tip wear.
Looking for atomic force microscope? Find out information about atomic force microscope. device that uses a spring-mounted probe to image individual atoms on the surface of a material, first developed by Gerd Binnig Binnig, Gerd , 1947-, German... Explanation of atomic force microscope
TY - CHAP. T1 - Characterization of DNA bound cyclic GMP-AMP synthase using atomic force microscopy imaging. AU - Lushnikov, Alexander. AU - Hooy, Richard. AU - Sohn, Jungsan. AU - Krasnoslobodtsev, Alexey. PY - 2019/1/1. Y1 - 2019/1/1. N2 - The protocol described herein allows for acquiring topography images of DNA-protein complexes using Atomic Force Microscopy imaging. Since the very beginning of this method, AFM has been an indispensable tool for characterization of biomolecular complexes with exceptional capability of observing single complexes. This method can visualize structural characteristics of DNA-protein assemblies and evaluate differences between individual complexes. Although this protocol is generally applicable to a large number of various proteins complexed with DNA, we use cyclic G/AMP synthase (cGAS) enzyme as a case study for the protocol description.. AB - The protocol described herein allows for acquiring topography images of DNA-protein complexes using Atomic Force ...
Park Systems provides the widest range of atomic force microscopes and Bio SICM featuring one-click AFM imaging and True Non-Contact atomic force microscopy.
Knowledge of the surface properties of microbial cells is a key to gain a detailed understanding of their functions in the natural environment and to efficiently exploit them in biotechnological processes. In this paper, we present force-distance curves recorded, by atomic force microscopy (AFM) in aqueous solutions, on various microbial samples: reconstituted S-layers, whole fungal spores and several bacterial strains. The approach and retraction curves exhibited important differences--depending on the type of microorganism, on the physiological state (dormancy versus germination) and on the environmental conditions (ionic strength)--which were shown to reflect differences in long-range surface forces, adhesion forces and mechanical properties. These data illustrate the great potential of AFM force measurements to elucidate the physical properties of microbial cells and to understand, at the molecular level, biointerfacial phenomena such as cell adhesion and cell aggregation. ...
When a material breaks into more than one piece, the cleavage occurs through some combination of brittle and ductile failure. During brittle failure, bonds are ruptured and there is little overall stretching of the material. During ductile failure, atoms or molecules slide past each other and the material deforms plastically before finally breaking. Glass is typically thought to break only through brittle failure, although it is known that plastic deformation will occur when glass is indented or scratched. Recent observations also suggested that cavities formed during glass fracture, implying that brittle materials also fracture via plastic flow instead of via bond rupture.. Guin and Wiederhorn used atomic force microscopy to study the topology of slowly fractured silica and soda-lime-silicate glasses. Mapping the high-contrast points from one of the fracture surfaces revealed that they mirror those on the opposing surface. Line scans of the two surfaces revealed that the vertical error between ...
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Several techniques have been used in studying the structure of DNA, one of which is electron microscopy (EM). However, several issues on sample preservation have arisen with this technique due to its tedious sample preparation requirements. As a result, the atomic force microscope (AFM) was developed to overcome such shortcomings.
Recent developments in dynamic Atomic Force Microscopy where several eigenmodes are simultaneously excited in liquid media are proving to be an excellent tool in biological studies. Despite its relevance, the search for a reliable, efficient, and strong cantilever excitation method is still in progress. Herein, we present a theoretical modeling and experimental results of different actuation methods compatible with the operation of Atomic Force Microscopy in liquid environments: ideal acoustic, homogeneously distributed force, distributed applied torque (MAC Mode™), photothermal and magnetostrictive excitation. From the analysis of the results, it can be concluded that magnetostriction is the strongest and most efficient technique for higher eigenmode excitation when using soft cantilevers in liquid media. ...
2014 AIP Publishing LLC. Recent developments in dynamic Atomic Force Microscopy where several eigenmodes are simultaneously excited in liquid media are proving to be an excellent tool in biological studies. Despite its relevance, the search for a reliable, efficient, and strong cantilever excitation method is still in progress. Herein, we present a theoretical modeling and experimental results of different actuation methods compatible with the operation of Atomic Force Microscopy in liquid environments: ideal acoustic, homogeneously distributed force, distributed applied torque (MAC Mode™), photothermal and magnetostrictive excitation. From the analysis of the results, it can be concluded that magnetostriction is the strongest and most efficient technique for higher eigenmode excitation when using soft cantilevers in liquid media ...
With its ability to explore the surface of the sample by means of a local scanning probe and its use of dedicated software allows to be visualize results, atomic force microscopy (AFM) has revolutionized the study of the smallest aspects of life. Atomic Force Microscopy in Biomedical Research:
Evaluation of peptide-material interaction by force mapping method with an atomic force microscopeEvaluation of peptide-material interaction by force mapping method with an atomic force microscope ...
TY - JOUR. T1 - The micro-mechanics of single molecules studied with atomic force microscopy. AU - Fisher, Thomas E.. AU - Marszalek, Piotr E.. AU - Oberhauser, Andres. AU - Carrion-Vazquez, Mariano. AU - Fernandez, Julio M.. PY - 1999/10/1. Y1 - 1999/10/1. N2 - The atomic force microscope (AFM) in its force-measuring mode is capable of effecting displacements on an angstrom scale (10 Å = 1 nm) and measuring forces of a few piconewtons. Recent experiments have applied AFM techniques to study the mechanical properties of single biological polymers. These properties contribute to the function of many proteins exposed to mechanical strain, including components of the extracellular matrix (ECM). The force-bearing proteins of the ECM typically contain multiple tandem repeats of independently folded domains, a common feature of proteins with structural and mechanical roles. Polysaccharide moieties of adhesion glycoproteins such as the selectins are also subject to strain. Force-induced extension of ...
Understanding how cell adhesion proteins form adhesion domains is a key challenge in cell biology. Here, we use single-molecule atomic force microscopy (AFM) to demonstrate the force-induced formation and propagation of adhesion nanodomains in living fungal cells, focusing on the covalently anchored cell-wall protein Als5p from Candida albicans. We show that pulling on single adhesins with AFM tips terminated with specific antibodies triggers the formation of adhesion domains of 100-500 nm and that the force-induced nanodomains propagate over the entire cell surface. Control experiments (with cells lacking Als5p, single-site mutation in the protein, bare tips, and tips modified with irrelevant antibodies) demonstrate that Als5p nanodomains result from protein redistribution triggered by force-induced conformational changes in the initially probed proteins, rather than from nonspecific cell-wall perturbations. Als5p remodeling is independent of cellular metabolic activity because heat-killed ...
The self-assembly of peptides and proteins into amyloid fibrils of nanometric thickness and up to several micrometres in length, a phenomenon widely observed in biological systems, has recently aroused a growing interest in nanotechnology and nanomedicine. Here we have applied atomic force microscopy and single molecule force spectroscopy to study the amyloidogenesis of a peptide derived from human amylin and of its reverse sequence. The spontaneous formation of protofibrils and their orientation along well-defined directions on graphite and DMSO-coated graphite substrates make the studied peptides interesting candidates for nanotechnological applications. The measured binding forces between peptides correlate with the number of hydrogen bonds between individual peptides inside the fibril structure according to molecular dynamics simulations ...
Currently, there is a growing need for methods that can quantify and map the molecular interactions of biological samples, both with high-force sensitivity and high spatial resolution. Force-distance (FD) curve-based atomic force microscopy is a valuable tool to simultaneously contour the surface and map the biophysical properties of biological samples at the nanoscale. In this webinar, we will report the use of advanced FD-based technology combined with chemically functionalized tips to probe the localization and interactions of chemical and biological sites on single native proteins and on living cells at high-resolution. I will present how an atomic force and confocal microscopy set-up allows the surface receptor landscape of cells to be imaged and the virus binding events within the first millisecond of contact with the cell to be mapped at high resolution (,50 nm). I will also highlight theoretical approaches to contour the free-energy landscape of early binding events between an engineered ...
Deflection images of living outer Annulus cells from Bovine Intervertebral discs, day 6 (after seeding), imaged in culture medium containing 10% fetal bovine serum (FBS) using Contact Mode. Left image was acquired before a series of force curves were taken on the area of the cell that is circled in red. Right image was acquired 45 minutes later. Displayed force curve was acquired on the cell marked with an "X". It can be clearly seen that the cells have moved, undergone cytoskeletal reorganization and, where the force curves were taken, were damaged by the AFM tip, 54µm.. Data Courtesy of Y. Dror and J. Klein, Oxford University and Weizmann Institute, NanoInteract consortium.. ...
Abstract: This thesis uses a Veeco Icon Atomic Force Microscope (AFM) to educate undergraduate students about the nanoscale world and to perform archaeological research. In chapter 2, an educational resource is developed to provide hands-on nanotechnology experience for undergraduate students. With the rapid growth of atomic force microscopy at many levels of industry and academia, it is important to expose the next generation to this technique. This learning module attempts to provide an experimental approach to learning about AFM phase imaging and its many applications. In chapters 3 and 4, AFM is used as one of several techniques for classifying the use of Neanderthal flint tools from Weasel Cave, Russia. These stone tools were identified as being used for tasks such as wood working, hide scraping, and meat cutting. Depending on the type of flint and the task involved, various degrees of abrasion occurred, leaving behind microwear polishes. These microwear traces are localized regions where ...
DNA is the bio-polymer containing the genetic information needed for the development and functioning for all living organisms. It has a polymeric structure consisting of units called nucleotides, each consisting of a non-polar, hydrophobic interior (the base pairs) and polar, hydrophilic exterior which is negatively charged due to the phosphate groups along the backbone of the DNA. Its heterogeneous properties permit DNA molecule to interact with other molecules and different types of substrates at the same time. It is important to understand the DNA morphology on flat surface that serves as a template for DNA based sensors and microarray applications, particularly under an electric field. Taken together, the ability to deposit a single DNA molecule on the electrode is essential to increase its specificity. In our study, we optimize the conditions in order to control a single DNA molecule adsorbing and desorbing to/from the electrode. Simultaneously dynamic imaging enables us to analyze its ...
单分子力谱 的翻译结果:single-molecule force spectroscopy;single molecule force spectroscopy;single molecular force spectroscopy||双语例句|英文例句|相关文摘
The noncovalent analogues of antitumor polynuclear platinum complexes represent a structurally discrete class of platinum drugs. Their chemical and biological properties differ significantly from those of most platinum chemotherapeutics, which bind to DNA in a covalent manner by formation of Pt-DNA adducts. In spite of the fact that these noncovalent polynuclear platinum complexes contain no leaving groups, they have been shown to bind to DNA with high affinity. We report here on the DNA condensation properties of a series of noncovalent analogues of antitumor polynuclear platinum complexes described by biophysical and biochemical methods. The results demonstrate that these polynuclear platinum compounds are capable of inducing DNA condensation at more than 1 order of magnitude lower concentrations than conventional spermine. Atomic force microscopy studies of DNA condensation confined to a mica substrate have revealed that the DNA morphologies become more compact with increasing concentration ...
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Scanning force microscopy was used to investigate the conformation of hypotonic spread chicken erythrocyte nucleosomes. Nucleosomal chains were prepared in low-salt conditions and fixed before centrifugation onto glass coverslips and air drying. The images of single nucleosomes were isolated by image processing, and the height and geometry of the resulting three-dimensional structures were investigated. An average nucleosome height of 4.2 +/- 1.1 nm was determined. A virtual cross section at half-maximum height of the nucleosome structure was used for a characterization of the nucleosome geometry. The shape of this cross section was best described by an ellipse with an aspect ratio (major/minor axis) of approximately 1.30.
Effect of clay platelet orientation on spin cast nanocomposite films. Li, J.; Schwarz, S. A.; Ji, Y.; Rafailovich, M. H.; Sokolov, J.; Rudomen, G.; Feng, W. H. // Applied Physics Letters;9/11/2006, Vol. 89 Issue 11, p111917 The authors show that the thickness of spin cast nanocomposite polystyrene/clay films displays a large radial dependence that is not explained by current models. Transmission electron microscopy and atomic force microscopy reveal a tendency for the high aspect ratio clay particles to align in... ...
TY - JOUR. T1 - Atomic force microscopy and real atomic resolution. Simple computer simulations. AU - Koutsos, V.. AU - Manias, E.. AU - Brinke, G. Ten. AU - Hadziioannou, G.. PY - 1994/4/10. Y1 - 1994/4/10. N2 - Using a simple computer simulation for AFM imaging in the contact mode, pictures with true and false atomic resolution are demonstrated. The surface probed consists of two f.c.c. (111) planes and an atomic vacancy is introduced in the upper layer. Changing the size of the effective tip and its registry with respect to the atoms of the crystal probed, images with completely different qualitative features are obtained. If the effective tip is a single atom the vacancy is clearly imaged. However, if the tip consists of several atoms and is in registry with the sample, a virtual atom appears instead of the vacancy and the crystal lattice is perfectly reproduced. If the tip is out of registry with respect to the sample, artifacts having the size of the effective tip are reported.. AB - Using ...
Nanoporous thin films with silver nanoparticles were synthesized with a bottom-up approach, and its potential as effective surfaceenhanced Raman scattering (SERS) substrates was demonstrated. The use of mesoporous titania films as substrates allowed to control the growth of nanoparticles on the film surface. Atomic force microscopy measurements, Ultraviolet-visible and X-ray diffraction analysis confirmed the photoreduction of Ag+ to Ag0 with the formation of nanoparticles with crystallite dimensions of 32 to 36 nm. The new substrates allowed the detection of two analytes (rhodamine B isothiocyanate and cytochrome c), present in solutions at very low concentrations, highlighting their potential in SERS sensing. Reproducibility, homogeneity, enhancement factor of the substrate, consistency of results and detection limits were also assessed. ...
Gadolinium oxide is an excellent optical material that offers high transmission in a wide wavelength range of 200-1600 nm and exhibits a high bulk refractive index of ∼1.80 at 550 nm. In the present study, a set of Gd2O3 thin films has been deposited on fused silica substrates by RF sputtering of a Gd2O3 target under various O2 to Ar flow ratios. The samples have been characterized by grazing incidence x-ray diffraction (GIXRD) to study the long range structural behavior, by GIXR to study density and surface roughness of the films, by atomic force microscopy measurements to study morphological properties, by Rutherford backscattering measurements for compositional studies, and by transmission spectrophotometry and spectroscopic ellipsometry techniques to study their optical properties ...
Bismuth selenide Bi{sub 2}Se{sub 3} was grown by molecular beam epitaxy, while carrier density and mobility were measured directly in situ as a function of film thickness. Carrier density shows high interface n-doping (1.5 × 10{sup 13 }cm{sup −2}) at the onset of film conduction and bulk dopant density of ∼5 × 10{sup 11 }cm{sup −2} per quintuple-layer unit, roughly independent of growth temperature profile. Mobility depends more strongly on the growth temperature and is related to the crystalline quality of the samples quantified by ex-situ atomic force microscopy measurements. These results indicate that Bi{sub 2}Se{sub 3} as prepared by widely employed parameters is n-doped before exposure to atmosphere, the doping is largely interfacial in origin, and dopants are not the limiting disorder in present Bi{sub 2}Se{sub 3} films. ...
Specific molecular-receptor interactions with gut epithelium cells are important in understanding bioactivity of food components and drugs, binding of commensal microflora, attachment and initiation of defense mechanisms against pathogenic bacteria and for development of targeted delivery systems to the gut. However, methods for probing such interactions are lacking. Methodology has been developed and validated to measure specific molecular-receptor interactions on living human colorectal cancer cells as in vitro models for the gut epithelium. Atomic force microscopy (AFM) was used to measure ligand-receptor interactions and to map receptor locations on cell surfaces. Measurements were made using silica beads attached to the AFM tip- cantilever assembly, which were functionalized by coupling of ligands to the bead surface. Wheat germ agglutinin (WGA) binds to the glycosylated extracellular domain III of the epidermal growth factor receptor. Methodology was tested by measuring binding of WGA to ...
Researchers at ETH Z rich, EPF Lausanne and University of Fribourg have teamed up to take Atomic Force Microscopy images of the fibers and to analyze them using concepts from polymer physics and theoretical modeling. This combination of expertise has lead them to propose a set of general rules governing the assembly of filaments into thicker and twisted ribbon like fibers. Their results are published in the current issue of the scientific journal Nature Nanotechnology. "The model that we propose is extremely precise in its predictions", says Raffaele Mezzenga, Professor of Food and Soft Materials Sciences at the ETH Z rich. "Up to now there was no such exact and general model for the formation of Amyloid fibers", continues Giovanni Dietler, Professor of Physics of Living Matter, at the EPF Lausanne ...
TipsNano All Types of AFM Probes‎ - AFM Probes, AFM Cantilever, AFM Tips, AFM Cantilevers, AFM Cantilever Types, AFM, Probes, TipsNano, TipsNano webshop Website Kristiina 15-214 10131 ...
AMELIA GAMAN 1,2, E. OSIAC 1, IONELA ROTARU 1,2, C.TAISESCU1 1 University of Medicine and Pharmacy of Craiova 2 Clinic of Hematology, Filantropia City Hospital of Craiova ABSTRACT:Atomic force microscopy (AFM) represents an important instrument for measuring mechanical properties of biological materials ranging from single molecules to normal or malignant cells. AFM provides a 3D profile of the surface on a nanoscale, by measuring forces between a sharp probe (
Cover: Barnacles adhere to surfaces in the marine environment using a proteinaceous cement. Liquid cement is released by ducts at the junction of the calcified base and lateral plates (X-ray microtomographs, foreground), and rapidly cures. Inspired by evolutionary concepts, Dickinson et al. (pp. 3499−3510) show that barnacle cement polymerization occurs by a biochemical mechanism strikingly similar to that of blood clotting. Like blood clotting, cement polymerization involves proteolytic activation of enzymes and structural precursors, transglutaminase cross-linking, assembly of fibrous proteins (atomic force microscopy image, background), and release of chemical signals. Images: G. H. Dickinson, R. K. Everett, K. J. Wahl and D. Rittschof. ...
Atomic force microscopy images reveal aryne possesses three consecutive carbon-carbon double bonds, rather than a single triple bond
Elimination of S. aureus with classic antibiotics is difficult, and the current study aimed to evaluate the efficacy of ethanolic extracts of propolis (EEP) against S. aureus cultivated in complex media or milk. EEP (0-0.5 mg ml(-1)) decreased growth of S. aureus in BHI media and 1 mg ml(-1) was bactericidal against washed cell suspensions (10(7) CFU ml(-1)). Propolis extracts also killed S. aureus cells resuspended in milk, but the bactericidal dose was at least 20-fold greater. Cultures that were transferred for at least 60 generations with sub-lethal doses of propolis did not change much their sensibility to EEP. Atomic force microscopy images revealed changes in morphology and cell size of S. aureus cells exposed to EEP (0.5 mg ml(-1 ...
Author: Bellina, P. J. et al.; Genre: Conference Paper; Published in Print: 2008; Keywords: MPI für Intelligente Systeme; Stuttgart Center for Electron Microscopy (StEM); ; Title: In-situ transmission electron microscopy investigation of TiO islands nucleating on SrTiO3 (100) and (110) surfaces at high temperature
The study on 2-D molybdenum disulfide (MoS2) defects employed low frequency noise measurements and conductive atomic force microscopy (C-AFM). The enlarged image shows an AFM cantilever tip pointing to an area with one sulfur monovacancy (area shaded red). As current flows through the AFM tip and the sample, switching events between different ionization states (neutral and charged -1) are measured. With a radius of around 25 nanometers, the AFM tip covers an area that contains around 1-8 sulfur monovacancies.
The versatility of chemical peptide synthesis combined with the high sensitivity of AFM single-molecule force spectroscopy allows us to investigate, quantify, and control molecular recognition processes (molecular nanotechnology), offering a tremendous potential in chemical biology. Single-molecule force spectroscopy experiments are able to detect fast intermediate transition states, details of the energy landscape, and structural changes, while avoiding multiple binding events that can occur under ensemble conditions. Dynamic force spectroscopy (DFS) is even able to provide data on the complex lifetime. This minireview outlines the biophysical methodology, discusses different experimental set-ups, and presents representative results in the form of two case studies, both dealing with DNA-binding peptides. They may serve as model systems, e.g., for transcription factors or gene transfection agents. Copyright (c) 2006 European Peptide Society and John Wiley & Sons, Ltd ...
Many researchers have studied the effects of changing the surface on fouling and cleaning. In biofouling the Baier curve is a well-known result which relates adhesion to surface energy, and papers on the effect of changing surface energy to food fouling can be found more than 40 years ago. Recently the use of modified surfaces, at least at a research level, has been widespread. Here two different ways of studying surface-deposit interactions have been compared. Atomic force microscopy (AFM) is a method for probing interactions at a molecular level, and can measure (for example) the interaction between substrate and surfaces at a nm-scale. At a μm-mm level, we have developed a micromanipulation tool that can measure the force required to remove the deposit; the measure incorporates both surface and bulk deformation effects. The two methods have been compared by studying a range of model soils: toothpaste, as an example of a soil that can be removed by fluid flow alone, and confectionery soils. ...
Figure 3. Schematic of atomic force microscopy. The quadrant photodiode detects deflections from the cantilever as it scans across the sample surface, interacting through attractive or repulsive forces. Image courtesy of JPK Instruments AG.. Having a background in both Biology and Physics, working in Dr. Zoya Leonenkos Nanoscale Biophysics Group is the perfect marriage for both my passions. I get to use methods and theories from physics to study a biological issue on the nanoscale. To study the effect of daptomycin on bacterial membrane and lung surfactant lipid models, I use atomic force microscopy (Figure 3) or AFM to observe any structural changes that take place in the presence of daptomycin by taking images of the samples surface. To understand how AFM works, imagine that the AFM has a tip that is comparable to the needle of a record player and that the sample surface is like the vinyl record. This tip runs back and forth along the sample surface, experiencing attractive and repulsive ...
A key consideration when developing a drug nanoparticle formulation, particularly when intended for parenteral administration, is the control of particle size, shape and physical properties such as dissolution rate and stability with respect to Ostwald ripening. These factors, in turn, determine the safety, shelf life and pharmacokinetic performance of such dosage forms. Consequently, applying meaningful approaches to the characterisation of drug nanoparticles is a prerequisite to the development of viable formulations. Atomic Force Microscopy has emerged as an important technique for studying particles in the colloidal size range. AFM allows detailed analysis of the dimensions and architecture of individual particles and is therefore complementary to
TY - JOUR. T1 - Atomic force microscopy of hyaluronan polysaccharide on differing surfaces. AU - Spagnoli, C. AU - Lyubchenko, Yuri L.. AU - Balazs, EA. AU - Cowman, Mary. PY - 2003. Y1 - 2003. M3 - Article. JO - Biophysical Journal. JF - Biophysical Journal. SN - 0006-3495. ER - ...