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Atomic force microscopy

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https://www.readbyqxmd.com/read/28922604/a-comparative-study-on-the-performance-of-inert-and-functionalized-spheres-coated-with-solid-dispersions-made-of-two-structurally-related-antifungal-drugs
#1
Naila A Mugheirbi, Peter O'Connell, Dolores R Serrano, Anne Marie Healy, Lynne S Taylor, Lidia Tajber
Fluid bed coating offers potential advantages as a formulation platform for amorphous solid dispersions (ASDs) of poorly soluble drugs, being a one-step manufacturing process which could reduce the risk of phase separation associated with multiple step manufacturing approaches. However, the impact of the physicochemical nature of carrier spheres on the properties and drug release from the ASDs has not been studied in detail. In this work, tartaric acid (TAP) and microcrystalline cellulose (CEL) spheres were chosen as examples of functional and inert beads, respectively...
September 18, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28921990/disruption-of-asymmetric-lipid-bilayer-models-mimicking-the-outer-membrane-of-gram-negative-bacteria-by-an-active-plasticin
#2
Jean-Philippe Michel, Yingxiong Wang, Irena Kiesel, Yuri Gerelli, Veronique Rosilio
The outer membrane (OM) of Gram-negative bacteria is a complex and asymmetric bilayer that antimicrobial peptides must disrupt in order to provoke the cell lysis. The inner and external leaflets of the OM are mainly composed of phospholipids (PL), and lipopolysaccharide (LPS), respectively. Supported lipid bilayers are interesting model systems to mimic the lipid asymmetric scaffold of the OM and determine the quantitative and mechanistic effect of antimicrobial agents, using complementary physicochemical techniques...
September 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28921710/non-stick-properties-of-thin-film-coatings-on-dental-restorative-instruments
#3
Jarmo Leppäniemi, Sasha Hoshian, Kimmo Suomalainen, Toni Luoto, Ville Jokinen, Jari Koskinen
The non-stick properties of thin-film coatings on dental-restorative instruments were investigated by static contact-angle measurement using dental filler resin as well as by scanning electron microscopy of the amount of sticking dental restorative material. Furthermore, using a customized dipping measurement set-up, non-stick properties were evaluated by measuring force-by-time when the instrument was pulled out of restorative material. Minor improvements in non-stick properties were obtained with commercial diamond-like carbon and commercial polytetrafluoroethylene-based coatings...
September 18, 2017: European Journal of Oral Sciences
https://www.readbyqxmd.com/read/28920669/in-situ-studies-of-solid-electrolyte-interphase-sei-formation-on-crystalline-carbon-surfaces-by-neutron-reflectometry-and-atomic-force-microscopy
#4
Miriam Steinhauer, Michael Stich, Mario Kurniawan, Beatrix-Kamelia Seidlhofer, Marcus Trapp, Andreas Bund, Norbert Wagner, K Andreas Friedrich
The solid electrolyte interphase (SEI) is a complex and fragile passivation layer with crucial importance for the functionality of lithium-ion batteries. Due to its fragility and reactivity, the use of in situ techniques is preferable for the determination of the SEI's true structure and morphology during its formation. In this study, we use in situ neutron reflectometry (NR) and in situ atomic force microscopy (AFM) to investigate the SEI formation on a carbon surface. It was found that a lithium rich adsorption layer is already present at the open circuit voltage on the carbon sample surface and that the first decomposition products start to deposit close to this potential...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28920607/tuning-the-electronic-environment-of-zinc-ions-with-a-ligand-for-dendrite-free-zinc-deposition-in-an-ionic-liquid
#5
Zhen Liu, Guozhu Li, Tong Cui, Abhishek Lahiri, Andriy Borodin, Frank Endres
In this work, we report on the influence of an organic ligand on the electrodeposition of Zn from an ionic liquid (IL) electrolyte. Zinc oxide was first dissolved in a protic IL. By introducing a 2-methylimidazole (2-MIm) ligand, the electronic environment of zinc ions, Zn(ii) complexes and the structure of the IL are considerably altered, as verified by both X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Due to the electron donation effect of the ligand, the zinc ions become less positively charged and exhibit a lower binding energy by -0...
September 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28920438/conduction-mechanisms-at-interface-of-aln-sin-dielectric-stacks-with-algan-gan-heterostructures-for-normally-off-high-electron-mobility-transistors-correlating-device-behavior-with-nanoscale-interfaces-properties
#6
Giuseppe Greco, Patrick Fiorenza, Ferdinando Iucolano, Andrea Severino, Filippo Giannazzo, Fabrizio Roccaforte
In this work, the conduction mechanisms at the interface of AlN/SiN dielectric stacks with AlGaN/GaN heterostructures have been studied combining different macroscopic and nanoscale characterizations on bare materials and devices. The AlN/SiN stacks grown on the recessed region of AlGaN/GaN heterostructures have been used as gate dielectric of hybrid metal-insulator-semiconductor high electron mobility transistors (MISHEMTs), showing a normally-off behaviour (Vth=+1.2 V), high channel mobility (204 cm(2)V(-1)s(-1)), and very good switching behaviour (ION/IOFF current ratio of 5-6×10(8) and sub-threshold swing of 90 mV/dec)...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28920436/rational-design-of-solution-processed-ti-fe-o-ternary-oxides-for-efficient-planar-ch3nh3pbi3-perovskite-solar-cells-with-suppressed-hysteresis
#7
Xin Li, Feng Hao, Xingyue Zhao, Xuewen Yin, Zhibo Yao, Ying Guo, Heping Shen, Hong Lin
Electron extraction layer (EEL) plays a critical role in organometal-halide perovskite solar cells (PSCs) by determining the charge extraction and ultimately their power conversion efficiencies. Here, Ti-Fe-O ternary oxide was firstly demonstrated as an efficient EEL candidate in the planar PSC, showing superiority in multiple aspects including the intrinsic precursor stability, coverage on the substrates, electrical properties, and energy levels compared to the widely used TiOx and the pure FeOx. By varying Fe content from 0% to 100% in the Ti-Fe-O composite, the conductivities of the resultant compact layers were markedly improved, according to consistent results from conductive atomic force microscopy (CAFM) and linear sweep voltammetry (LSV) measurements...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28919752/zinc-oxide-nanoparticles-induce-apoptosis-and-autophagy-in-human-ovarian-cancer-cells
#8
Ding-Ping Bai, Xi-Feng Zhang, Guo-Liang Zhang, Yi-Fan Huang, Sangiliyandi Gurunathan
BACKGROUND: Zinc oxide nanoparticles (ZnO NPs) are frequently used in industrial products such as paint, surface coating, and cosmetics, and recently, they have been explored in biologic and biomedical applications. Therefore, this study was undertaken to investigate the effect of ZnO NPs on cytotoxicity, apoptosis, and autophagy in human ovarian cancer cells (SKOV3). METHODS: ZnO NPs with a crystalline size of 20 nm were characterized with various analytical techniques, including ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and atomic force microscopy...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28919738/surface-modification-of-endovascular-stents-with-rosuvastatin-and-heparin-loaded-biodegradable-nanofibers-by-electrospinning
#9
Milka Janjic, Foteini Pappa, Varvara Karagkiozaki, Christakis Gitas, Kiriakos Ktenidis, Stergios Logothetidis
This study describes the development of drug-loaded nanofibrous scaffolds as a nanocoating for endovascular stents for the local and sustained delivery of rosuvastatin (Ros) and heparin (Hep) to injured artery walls after endovascular procedures via the electrospinning process. PURPOSE: The proposed hybrid covered stents can promote re-endothelialization; improve endothelial function; reduce inflammatory reaction; inhibit neointimal hyperplasia of the injured artery wall, due to well-known pleiotropic actions of Ros; and prevent adverse events such as in-stent restenosis (ISR) and stent thrombosis (ST), through the antithrombotic action of Hep...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28919343/characterizing-pathology-in-erythrocytes-using-morphological-and-biophysical-membrane-properties-relation-to-impaired-hemorheology-and-cardiovascular-function-in-rheumatoid-arthritis
#10
Oore-Ofe O Olumuyiwa-Akeredolu, Prashilla Soma, Antoinette V Buys, Legesse Kassa Debusho, Etheresia Pretorius
The inflammatory burden of the complex Rheumatoid Arthritis (RA) disease affects several organ-systems, including rheological properties of blood and its formed elements. Red blood cells (RBCs) are constantly exposed to circulating dysregulated inflammatory molecules that are co-transported within the vasculature; and their membranes may be particularly vulnerable to the accompanying oxidative stress. In the current study, we investigate biophysical and ultrastructural characteristics of RBCs obtained from a cohort of patients using atomic force microscopy (AFM), scanning electron microscopy (SEM) and confocal microscopy (CM)...
September 14, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28919310/cadherin-11-promotes-neural-crest-cell-spreading-by-reducing-intracellular-tension-mapping-adhesion-and-mechanics-in-neural-crest-explants-by-atomic-force-microscopy
#11
REVIEW
Carina Blaue, Jubin Kashef, Clemens M Franz
During development cranial neural crest cells (NCCs) display a striking transition from collective to single-cell migration, but the mechanisms enabling individual NCCs to separate from the neural crest tissue are still incompletely understood. In this study we have employed atomic force microscopy (AFM) to investigate potential adhesive and mechanical changes associated with the dissociation of individual cells from cohesive Xenopus NCC explants at early stages of migration. AFM-based single-cell force spectroscopy (SCFS) revealed a uniform distribution of cell-cell adhesion forces within NCC explants, including semi-detached leader cells in the process of delaminating from the explant edge...
September 14, 2017: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/28918188/the-effect-of-thiolated-phospholipids-on-formation-of-supported-lipid-bilayers-on-gold-substrates-investigated-by-surface-sensitive-methods
#12
Abdulhalim Kılıç, M Fazeli Jadidi, Hakan Özgür Özer, Fatma Neşe Kök
Most of the model lipid membrane studies on gold involve the usage of various surface-modification strategies to rupture liposomes and induce lipid bilayer formation since liposomes with polar surfaces do not interact with bare, hydrophobic gold. In this study, a thiol-modified phospholipid, 1,2-Dipalmitoyl-sn-Glycero-3-Phosphothioethanol (DPPTE) was incorporated into phosphatidylcholine (PC) based liposomes to form supported lipid bilayer (SLB) on gold surfaces without further modification. The binding kinetics of liposomes with different DPPTE ratio (0...
September 8, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28917880/intercalated-chitosan-hydroxyapatite-nanocomposites-promising-materials-for-bone-tissue-engineering-applications
#13
Muhammad Anwaar Nazeer, Emel Yilgör, Iskender Yilgör
Preparation and characterization of chitosan/hydroxyapatite (CS/HA) nanocomposites displaying an intercalated structure is reported. Hydroxyapatite was synthesized through sol-gel process. Formic acid was introduced as a new solvent to obtain stable dispersions of nano-sized HA particles in polymer solution. CS/HA dispersions with HA contents of 5, 10 and 20% by weight were prepared. Self-assembling of HA nanoparticles during the drying of the solvent cast films led to the formation of homogeneous CS/HA nanocomposites...
November 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28917871/inhibition-of-gelatinized-rice-starch-retrogradation-by-rice-bran-protein-hydrolysates
#14
Liya Niu, Leiyan Wu, Jianhui Xiao
The retrogradation of gelatinized rice starch (GRS) during the shelf life of a product is the biggest barrier related to starch-containing foods. The objective of this study was to produce rice bran protein hydrolysate (RBPH) using proteolytic enzymes (alcalase, flavourzyme, protamex, neutrase, bromelain, papain and trypsin) to suppress the retrogradation of GRS and understand the physical phenomena underlying the reduced retrogradation of GRS by RBPH during short- and long-term storage. Mixtures of GRS incorporated with Protamex-hydrolyzed rice bran protein at 1h (PRBPH-1) at a degree of hydrolysis of 15...
November 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28917800/%C3%AE-cyclodextrins-incorporated-multi-walled-carbon-nanotubes-modified-electrode-for-the-voltammetric-determination-of-the-pesticide-dichlorophen
#15
Karolina Sipa, Mariola Brycht, Andrzej Leniart, Paweł Urbaniak, Agnieszka Nosal-Wiercińska, Bartłomiej Pałecz, Sławomira Skrzypek
In this work, a glassy carbon electrode modified with β-cyclodextrins and multi-walled carbon nanotubes (β-CDs/MWCNTs/GCE) was constructed and applied for the square-wave adsorptive stripping voltammetric (SWAdSV) determination of the pesticide dichlorophen (Dcp). For the first time, this compound was electrochemically investigated. The voltammetric measurements were conducted in phosphate buffer (PBS) at pH 6.5 as a supporting electrolyte, and SWAdSV technique parameters were optimized. A linear calibration curve in the wide concentration range from 5...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917581/an-engineering-insight-into-the-relationship-of-selective-cytoskeletal-impairment-and-biomechanics-of-hela-cells
#16
Daniele Borin, Luca Puzzi, Valentina Martinelli, Matteo Cibinel, Romano Lapasin, Orfeo Sbaizero
It is widely accepted that the pathological state of cells is characterized by a modification of mechanical properties, affecting cellular shape and viscoelasticity as well as adhesion behaviour and motility. Thus, assessing these parameters could represent an interesting tool to monitor disease development and progression, but also the effects of drug treatments. Since biomechanical properties of cells are strongly related to cytoskeletal architecture, in this work we extensively studied the effects of selective impairments of actin microfilaments and microtubules on HeLa cells through force-deformation curves and stress relaxation tests with atomic force microscopy...
September 8, 2017: Micron: the International Research and Review Journal for Microscopy
https://www.readbyqxmd.com/read/28916996/successive-release-of-tissue-inhibitors-of-metalloproteinase-1-through-graphene-oxide-based-delivery-system-can-promote-skin-regeneration
#17
Cheng Zhong, Dike Shi, Yixiong Zheng, Peter J Nelson, Qi Bao
The purpose of this study was to testify the hypothesis that graphene oxide (GO) could act as an appropriate vehicle for the release of tissue inhibitors of metalloproteinase-1 (TIMP-1) protein in the context of skin repair. GO characteristics were observed by scanning electron microscopy, atomic force microscopy, and thermal gravimetric analysis. After TIMP-1 absorbing GO, the release profiles of various concentrations of TIMP-1 from GO were compared. GO biocompatibility with fibroblast viability was assessed by measuring cell cycle and apoptosis...
September 15, 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28916435/a-novel-electrochemical-immunosensor-based-on-ito-modified-by-carboxyl-ended-silane-agent-for-ultrasensitive-detection-of-mage-1-in-human-serum
#18
Aslı Gündoğdu, Elif Burcu Aydın, Mustafa Kemal Sezgintürk
A new, low-cost electrochemical immunosensor was developed for rapid detection of Melanoma-associated antigen 1 (MAGE-1), a cancer biomarker. The fabrication procedure of immunosensor was based on the covalent immobilization of anti-MAGE-1, biorecognition molecule, on ITO electrode by carboxyethylsilanetriol (CTES) monolayer. The biosensing MAGE-1 antigen was monitored by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) technique. Apart from these techniques, single frequency impedance (SFI) was used for investigation of antibody-antigen interactions...
September 12, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28915484/spontaneous-vesicle-formation-and-vesicle-to-micelle-transition-of-sodium-2-ketooctanate-in-water
#19
Huifang Xu, Na Du, Yawen Song, Shue Song, Wanguo Hou
Single-tailed short-chain alkyl keto-acids/salts, a class of fatty acid/salt derivatives, such as sodium 2-ketooctanate (KOCOONa), are a kind of weakly acid/salt type amphiphiles and plausible prebiotic molecules, and the current understanding of their aggregation behavior in aqueous solutions is still limited. Herein, the aggregation behavior of KOCOONa in aqueous solution was studied by changing its concentration (C), using equilibrium surface tension, conductivity, and fluorescence measurements. The aggregates formed were characterized using freeze-fracture and cryogenic transmission electron microscopy, dynamic light scattering, atomic force microscopy, and confocal laser scanning microscopy...
September 7, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28914536/determination-of-the-true-lateral-grain-size-in-organic-inorganic-halide-perovskite-thin-films
#20
Gordon A MacDonald, Chelsea M Heveran, Mengjin Yang, David Moore, Kai Zhu, Virginia L Ferguson, Jason P Killgore, Frank William DelRio
In this letter, methylammonium lead iodide (MAPbI3) thin films were examined via piezoresponse force microscopy (PFM) and nanoindentation (NI) to determine if long-range atomic order existed across the full width and depth of the apparent grains. From the PFM, the piezoelectric response of the films was strongly correlated with low-index planes of the crystal structure and ferroelastic domains in macro-scale solution-grown MAPbI3 crystals, which implied long-range order near the top surface. From the NI, it was found that the induced cracks were straight and extended across the full width of the apparent grains, which indicated that the long-range order was not limited to the near-surface region, but extended through the film thickness...
September 15, 2017: ACS Applied Materials & Interfaces
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