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Atomic force microscopy

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https://www.readbyqxmd.com/read/28812878/nanomechanical-imaging-of-the-diffusion-of-fullerene-into-conjugated-polymer
#1
Dong Wang, Ken Nakajima, Feng Liu, Shaowei Shi, Thomas P Russell
The large Young's modulus difference between chemically modified fullerene (PCBM) and a conjugated polymer was used to nanomechanically map the diffusion of PCBM into PTB7, a high efficiency low band gap conjugated polymer. The sharp tip in nanomechanical atomic force microscopy (AFM) ensures a high-resolution nanomechanical characterization of the diffusion front, with the intrinsic benefits of revealing the mechanical properties of the mixtures. Localized structure changes induced by diffusion were investigated by grazing incidence x-ray diffraction methods...
August 16, 2017: ACS Nano
https://www.readbyqxmd.com/read/28812363/influence-of-oxygen-vacancies-on-the-frictional-properties-of-nanocrystalline-zinc-oxide-thin-films-in-ambient-conditions
#2
Huan-Pu Chang, En-De Chu, Yu-Ting Yeh, Yueh-Chun Wu, Fang-Yuh Lo, Wei-Hua Wang, Ming-Yau Chern, Hsiang-Chih Chiu
Oxygen vacancy is the most studied point defect and has been found to significantly influence the physical properties of zinc oxide (ZnO). By using atomic force microscopy (AFM), we show that the frictional properties on the ZnO surface at the nanoscale greatly depend on the amount of oxygen vacancies present in the surface layer and the ambient humidity. The photocatalytic effect (PCE) is used to qualitatively control the amount of oxygen vacancies in the surface layer of ZnO and reversibly switch the surface wettability between hydrophobic and superhydrophilic states...
August 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28812314/self-assembled-chiral-nanostructures-of-amphiphilic-peptide-from-single-molecule-to-aggregate
#3
Ting Zhou, Zhiqing Zhang, Xuemei Zhang, Chen Wang, Guiying Xu, Yanlian Yang
We report interesting hierarchical self-assembled architectures from a designed amphiphilic peptide. The bisignate cotton effects in circular dichroism spectra show typical peptide aggregation-induced. The observation of peptide assembly structures from initial particles and fibrils to ribbon structures is supported by microscopy (atomic force microscopy and transmission electron microscopy). The visualization of individual peptide at the single molecular level offered insights of the intermolecular interactions responsible for the formation of aggregates, which is investigated by scanning tunneling microscopy...
August 15, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
https://www.readbyqxmd.com/read/28812215/proteomic-alterations-associated-with-biomechanical-dysfunction-are-early-processes-in-the-emilin1-deficient-mouse-model-of-aortic-valve-disease
#4
P M Angel, D A Narmoneva, M K Sewell-Loftin, C Munjal, L Dupuis, B J Landis, A Jegga, C B Kern, W D Merryman, H S Baldwin, G M Bressan, Robert B Hinton
Aortic valve (AV) disease involves stiffening of the AV cusp with progression characterized by inflammation, fibrosis, and calcification. Here, we examine the relationship between biomechanical valve function and proteomic changes before and after the development of AV pathology in the Emilin1-/- mouse model of latent AV disease. Biomechanical studies were performed to quantify tissue stiffness at the macro (micropipette) and micro (atomic force microscopy (AFM)) levels. Micropipette studies showed that the Emilin1-/- AV annulus and cusp regions demonstrated increased stiffness only after the onset of AV disease...
August 15, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28812063/self-organization-of-amino-acid-derived-ndi-assemblies-into-a-nanofibrillar-superstructure-with-humidity-sensitive-n-type-semiconducting-properties
#5
Marco A Squillaci, Grzegorz Markiewicz, Anna Walczak, Artur Ciesielski, Artur R Stefankiewicz, Paolo Samorì
The hierarchical self-assembly of l-tyrosine substituted naphthalenediimide has been explored in solution by NMR spectroscopy and in the solid-state by atomic force microscopy. Spontaneous non-covalent polymerisation led to the formation of a three-dimensional fibre-like supramolecular polymer with n-type semiconducting properties.
August 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28811262/probe-microscopy-methods-and-applications-in-imaging-of-biological-materials
#6
REVIEW
Alper D Ozkan, Ahmet E Topal, Fatma B Dikecoglu, Mustafa O Guler, Aykutlu Dana, Ayse B Tekinay
Atomic force microscopy is an emerging tool for investigating the biomolecular aspects of cellular interactions; however, cell and tissue analyses must frequently be performed in aqueous environment, over rough surfaces, and on complex adhesive samples that complicate the imaging process and readily facilitate the blunting or fouling of the AFM probe. In addition, the shape and surface chemistry of the probe determine the quality and types of data that can be acquired from biological materials, with certain information becoming available only within a specific range of tip lengths or diameters, or through the assistance of specific chemical or biological functionalization procedures...
August 12, 2017: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/28809547/quantitative-evaluation-of-viral-protein-binding-to-phosphoinositide-receptors-and-pharmacological-inhibition
#7
Seong-Oh Kim, Joshua Alexander Jackman, Menashe Elazar, Sang-Joon Cho, Jeffrey S Glenn, Nam-Joon Cho
There is significant interest in developing analytical methods to characterize molecular recognition events between proteins and phosphoinositides, which are a medically important class of carbohydrate-functionalized lipids. Within this scope, one area of high priority involves quantitatively evaluating drug candidates that pharmacologically inhibit protein-phosphoinositide interactions. As full-length proteins are oftentimes difficult to produce, establishing methods to study these interactions with shorter, bioactive peptides would be advantageous...
August 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28809419/environmental-stability-of-2d-anisotropic-tellurium-containing-nanomaterials-anisotropic-to-isotropic-transition
#8
Sijie Yang, Hui Cai, Bin Chen, Changhyun Ko, V Ongun Özçelik, D Frank Ogletree, Claire E White, Yuxia Shen, Sefaattin Tongay
We report on the vibrational (Raman) spectrum and structural transformation of semiconducting pseudo-1D GaTe and ZrTe3 nanomaterials driven by ambient molecular interactions at the nanoscale by angle-resolved Raman spectroscopy, atomic force microscopy (AFM), and environmental X-ray photoelectron (XPS) measurements. The results show that tellurium containing pseudo-1D materials undergo drastic structural and physical changes within a week. During this process, new Raman peaks start to emerge and surface roughness increases substantially...
August 15, 2017: Nanoscale
https://www.readbyqxmd.com/read/28809081/diagnosing-the-internal-architecture-of-zeolite-ferrierite
#9
Joel E Schmidt, Frank C Hendriks, Martin Lutz, L Christiaan Post, Donglong Fu, Dr Bert M Weckhuysen
Large crystals of zeolite ferrierite (FER) are important model systems for spatially resolved catalysis and diffusion studies, though there is considerable variation in crystal habit depending on the chemical composition and employed synthesis conditions. A synergistic combination of techniques has been applied, including single crystal X-ray diffraction, high-temperature in situ confocal fluorescence microscopy, fluorescent probe molecules, wide-field microscopy and atomic force microscopy to unravel the internal architecture of three distinct FER zeolites...
August 15, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28808261/atomic-force-microscopy-micro-rheology-reveals-large-structural-inhomogeneities-in-single-cell-nuclei
#10
Michael Lherbette, Ália Dos Santos, Yukti Hari-Gupta, Natalia Fili, Christopher P Toseland, Iwan A T Schaap
During growth, differentiation and migration of cells, the nucleus changes size and shape, while encountering forces generated by the cell itself and its environment. Although there is increasing evidence that such mechanical signals are employed to control gene expression, it remains unclear how mechanical forces are transduced through the nucleus. To this end, we have measured the compliance of nuclei by applying oscillatory strains between 1 and 700 Hz to individual nuclei of multiple mammalian cell-lines that were compressed between two plates...
August 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28807883/simultaneous-afm-topography-and-recognition-imaging-at-the-plasma-membrane-of-mammalian-cells
#11
REVIEW
Lilia A Chtcheglova, Peter Hinterdorfer
Elucidation the nano-organization of membrane proteins at/within the plasma membrane is probably the most demanding and still challenging task in cell biology since requires experimental approaches with nanoscale resolution. During last decade, atomic force microscopy (AFM)-based simultaneous topography and recognition imaging (TREC) has become a powerful tool to quickly obtain local receptor nano-maps on complex heterogeneous biosurfaces such as cells and membranes. Here we emphasize the TREC technique and explain how to unravel the nano-landscape of mammalian cells...
August 11, 2017: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/28807566/electrospun-collagen-based-nanofibres-a-sustainable-material-for-improved-antibiotic-utilisation-in-tissue-engineering-applications
#12
Ivan J Hall Barrientos, Eleonora Paladino, Peter Szabó, Sarah Brozio, Peter J Hall, Charles I Oseghale, Melissa K Passarelli, Susan J Moug, Richard A Black, Clive G Wilson, Romana Zelkó, Dimitrios A Lamprou
For the creation of scaffolds in tissue engineering applications, it is essential to control the physical morphology of fibres and to choose compositions which do not disturb normal physiological function. Collagen, the most abundant protein in the human body, is a well-established biopolymer used in electrospinning compositions. It shows high in-vivo stability and is able to maintain a high biomechanical strength over time. In this study, the effects of collagen type I in polylactic acid-drug electrospun scaffolds for tissue engineering applications are examined...
August 11, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28805394/high-efficiently-delaminated-single-layered-mxene-nanosheets-with-large-lateral-size
#13
Gengnan Li, Li Tan, Yumeng Zhang, Binghan Wu, Liang Li
Single layered Ti3C2(OH)2 nanosheets have been successfully fabricated by etching its Ti3AlC2 precursor with KOH in the presence of small amount of water. The OH group replaced the Al layer within Ti3AlC2 structure during etching process and Ti3C2(OH)2 nanosheets could be easily and efficiently achieved through a simple washing process. The delaminated single layered nanosheets are clearly revealed by atomic force microscopy to have several micrometers in lateral size. Interestingly, the exfoliated Ti3C2(OH)2 nanosheets could be restacked to form a new layer-structured material during drying process...
August 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28805366/simultaneous-top-and-bottom-perovskite-interface-engineering-by-fullerene-surface-modification-of-titanium-dioxide-as-electron-transport-layer
#14
John Ciro, Santiago Mesa, Juan Felipe Montoya, Jose Ignacio Uribe, Rafael Betancur, Franklin Jaramillo
Optimization of the interface between the electron transport layer (ETL) and hybrid perovskite is crucial to achieve high performance perovskite solar cell (PSC) devices. Fullerene-based compounds have attracted attention as modifiers on the surface properties of TiO2, the archetypal ETL in regular n-i-p PSCs. However, the partial solubility of fullerenes in the aprotic solvents used for perovskite deposition hinders its application to low-temperature solution-processed PSCs. In this work, we introduce a new method for fullerene modification of TiO2 layers derived from nanoparticles (NPs) inks...
August 14, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28805058/energy-level-alignment-of-a-hole-transport-organic-layer-and-ito-towards-applications-for-organic-electronic-devices
#15
Quentin Arnoux, Anthony Boucly, Vincent Barth, Rabah Benbalagh, Albano Cossaro, Luca Floreano, Mathieu G Silly, Fausto Sirotti, Etienne Derat, Stephane Carniato, Fabrice Bournel, Jean-Jacques Gallet, Denis Fichou, Ludovic Tortech, Francois Rochet
2,2',6,6'-tetraphenyl-4,4'-dipyranylidene (DIPO-Ph4) was grown by vacuum-deposition on an indium tin oxide (ITO) substrate. The films were characterized by atomic force microscopy and synchrotron radiation UV and X-ray photoelectron spectroscopy to gain an insight into the material growth and to better understand the electronic properties of the DIPO-Ph4/ITO interface. Results show formation of cationic DIPO-Ph4 at ITO interface with a charge transfer from the organic layer to the anode material. This has been confronted to DFT calculations...
August 14, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28803479/design-of-cyclic-peptides-based-glucose-receptors-and-their-application-in-glucose-sensing
#16
Chao Li, Xin Chen, Fuyuan Zhang, Xingxing He, Guozhen Fang, Jifeng Liu, Shuo Wang
Glucose assay is of great scientific significance in clinical diagnostics and bioprocess monitoring and to design new glucose receptor is necessary for development of more sensitive, selective and robust glucose detection techniques. Herein, a series of cyclic peptides (CPs) glucose receptor were designed to mimic the binding sites of glucose binding protein (GBP) and CPs' sequence contained amino acid sites Asp, Asn, His, Asp, Arg, which constituted the first layer interactions of GBP. The properties of these CPs used as a glucose receptor or substitute for the GBP were studied by using quartz crystal microbalance (QCM) technique...
August 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28803430/effects-of-stimulated-aggrecanolysis-on-nanoscale-morphological-and-mechanical-properties-of-wild-type-and-aggrecanase-resistant-mutant-mice-cartilages
#17
Md Hemayet Uddin, Huabin Wang, Fraser M Rogerson, Peter Vee-Sin Lee, Xuehua Zhang
A key event in arthritis pathogenesis is the degradation of aggrecan, the major component in articular cartilage. In this work, we investigate the effects of stimulated aggrecanolysis on the morphological and nanomechanical properties of cartilage harvested from wild-type mice and aggrecanase-resistant mutant mice named "Jaffa". The cartilages were native or were subjected to stimulated aggrecanolysis by interleukin-1[Formula: see text] (IL-1[Formula: see text]) treatment. The nanoscale morphological and mechanical properties of the sectioned cartilages were measured by using a sharp probe by atomic force microscopy (AFM)...
August 2017: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/28803055/aristolochic-acid-and-its-derivatives-as-inhibitors-of-snake-venom-l-amino-acid-oxidase
#18
Payel Bhattacharjee, Indrani Bera, Subhamoy Chakraborty, Nanda Ghoshal, Debasish Bhattacharyya
Snake venom L-amino acid oxidase (LAAO) exerts toxicity by inducing hemorrhage, pneumorrhagia, pulmonary edema, cardiac edema, liver cell necrosis etc. Being well conserved, inhibitors of the enzyme may be synthesized using the template of the substrate, substrate binding site and features of the catalytic site of the enzyme. Previous findings showed that aristolochic acid (AA), a major constituent of Aristolochia indica, inhibits Russell's viper venom LAAO enzyme activity since, AA interacts with DNA and causes genotoxicity, derivatives of this compound were synthesized by replacing the nitro group to reduce toxicity while retaining the inhibitory potency...
August 9, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28802697/the-insertion-of-polybia-mp1-into-phospholipid-monolayers-is-regulated-by-its-anionic-nature-and-phase-state
#19
Dayane S Alvares, Natalia Wilke, João Ruggiero Neto, Maria Laura Fanani
Polybia-MP1 or simply MP1 (IDWKKLLDAAKQIL-NH2) is a peptide with broad-spectrum bactericidal activity and a strong inhibitory effect against cancer cells. The aim of this work was to evaluate the effect of biophysical properties such as membrane texture and film thickness on MP1 interaction with neutral and anionic lipid membranes. For this purpose, we first explored the peptide's surface behavior. MP1 showed high surface activity, adsorbing onto bare air/aqueous interfaces up to higher surface pressures than the collapse pressure of MP1 Langmuir films...
August 9, 2017: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/28801568/atomic-force-microscopy-reveals-the-dynamic-morphology-of-fenestrations-in-live-liver-sinusoidal-endothelial-cells
#20
B Zapotoczny, K Szafranska, K Owczarczyk, E Kus, S Chlopicki, M Szymonski
Here, we report an atomic force microscopy (AFM)-based imaging method for resolving the fine nanostructures (e.g., fenestrations) in the membranes of live primary murine liver sinusoidal endothelial cells (LSECs). From data on topographical and nanomechanical properties of the selected cell areas collected within 1 min, we traced the dynamic rearrangement of the cell actin cytoskeleton connected with the formation or closing of cell fenestrations, both in non-stimulated LSECs as well as in response to cytochalasin B and antimycin A...
August 11, 2017: Scientific Reports
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