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Atomic force microscopy

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https://www.readbyqxmd.com/read/28532113/nanofibers-of-human-tropoelastin-inspired-peptides-structural-characterization-and-biological-properties
#1
Valeria Secchi, Stefano Franchi, Marco Fioramonti, Giovanni Polzonetti, Giovanna Iucci, Brigida Bochicchio, Chiara Battocchio
Regenerative medicine is taking great advantage from the use of biomaterials in the treatments of a wide range of diseases and injuries. Among other biomaterials, self-assembling peptides are appealing systems due to their ability to spontaneously form nanostructured hydrogels that can be directly injected into lesions. Indeed, self-assembling peptide scaffolds are expected to behave as biomimetic matrices able to surround cells, to promote specific interactions, and to control and modify cell behavior by mimicking the native environment as well...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532050/full-in-vitro-analyses-of-new-generation-bulk-fill-dental-composites-cured-by-halogen-light
#2
Tuçe Hazal Tekin, Aysel Kantürk Figen, Pınar Yılmaz Atalı, Bilge Coşkuner Filiz, Mehmet Burçin Pişkin
The objective of this study was to investigate the full in-vitro analyses of new-generation bulk-fill dental composites cured by halogen light (HLG). Two types' four composites were studied: Surefill SDR (SDR) and Xtra Base (XB) as bulk-fill flowable materials; QuixFill (QF) and XtraFill (XF) as packable bulk-fill materials. Samples were prepared for each analysis and test by applying the same procedure, but with different diameters and thicknesses appropriate to the analysis and test requirements. Thermal properties were determined by thermogravimetric analysis (TG/DTG) and differential scanning calorimetry (DSC) analysis; the Vickers microhardness (VHN) was measured after 1, 7, 15 and 30days of storage in water...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532029/surfactin-loaded-polyvinyl-alcohol-pva-nanofibers-alters-adhesion-of-listeria-monocytogenes-to-polystyrene
#3
J J Ahire, D D Robertson, A J van Reenen, L M T Dicks
Surfactin-loaded polyvinyl alcohol (PVA) nanofibers were spun using gravity electrospinning. Scanning electron microscopy (SEM) images showed that nanofibers spun with surfactin are free from bead formation and uniform in diameter. The average nanofiber diameters were decreased (273±39nm, 259±39nm and 217±33nm) with increasing levels of surfactin (0.5, 1.0 and 1.5%, w/v) into PVA (10%, w/v). The 10% (w/v) PVA had average fiber diameter of 303±33nm. Atomic force microscopy (AFM) analysis showed that fibers spun with surfactin are not smooth as PVA fibers...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531974/biomimetic-collagen-phospholipid-coatings-improve-formation-of-hydroxyapatite-nanoparticles-on-titanium
#4
Gilia C M Ruiz, Marcos A E Cruz, Amanda N Faria, Daniela C Zancanela, Pietro Ciancaglini, Ana P Ramos
Osseointegration between the surface of a certain material and the host tissue helps to evaluate the potential use of biomaterials in bone replacement. The physicochemical properties and biochemical composition of the material's surface regulates osseointegration. This study investigates how collagen into biomimetic matrixes affects hydroxyapatite (HAp) growth. Collagen was inserted into insoluble Langmuir monolayers containing either 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) or octadecylphosphonic acid (OPA) and transferred to titanium (Ti) supports by means of the Langmuir-Blodgett (LB) technique...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531263/in-vivo-dynamics-of-the-cortical-actin-network-revealed-by-fast-scanning-atomic-force-microscopy
#5
Yanshu Zhang, Aiko Yoshida, Nobuaki Sakai, Yoshitsugu Uekusa, Masahiro Kumeta, Shige H Yoshimura
Together with lamellipodia and stress fibers, a dynamic network of actin filaments in the cell cortex plays a major role in the maintenance of cell morphology and motility. In contrast to lamellipodia, which have been well studied in various motile cells, the dynamics of actin filaments in the cell cortex have not yet been clarified due to a lack of proper imaging techniques. Here, we utilized high-speed atomic force microscopy for live-cell imaging and analyzed cortical actin dynamics in living cells. We successfully measured the polymerization rate and the frequency of filament synthesis in living COS-7 cells, and examined the associated effects of various inhibitors and actin-binding proteins...
May 20, 2017: Microscopy
https://www.readbyqxmd.com/read/28530826/high-speed-atomic-force-microscopy-reveals-loss-of-nuclear-pore-resilience-as-a-dying-code-in-colorectal-cancer-cells
#6
Mahmoud Shaaban Mohamed, Akiko Kobayashi, Azuma Taoka, Takahiro Watanabe-Nakayama, Yosuke Kikuchi, Masaharu Hazawa, Toshinari Minamoto, Yoshihiro Fukumori, Noriyuki Kodera, Takayuki Uchihashi, Toshio Ando, Richard W Wong
Nuclear pore complexes (NPCs) are the sole turnstile implanted in the nuclear envelope (NE), acting as a central nano-regulator of transport between the cytosol and the nucleus. NPCs consist of ~30 proteins, termed nucleoporins. About one-third of nucleoporins harbour natively unstructured, intrinsically disordered phenylalanine-glycine strings (FG-Nups), which engage in transport selectivity. Because the barriers insert deeply in the NPC, they are nearly inaccessible. Several in vitro barrier models have been proposed; however, the dynamic FG-Nups protein molecules themselves are imperceptible in vivo...
May 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28530788/long-term-cyclability-of-electrochromic-poly-3-hexyl-thiophene-films-modified-by-surfactant-assisted-graphene-oxide-layers
#7
Tae-Ho Kim, Ki-In Choi, Hyeri Kim, Seong Hyeon Oh, Jaseung Koo, Yoon-Chae Nah
Organic electrochromic (EC) materials are generally known to be electrochemically unstable during the ionic exchange process. One effective method to stabilize them is incorporating graphene derivatives in the polymer matrix, thereby creating strong interaction between graphene derivatives and polymer. However, previous studies are limited to specific polymers and bulk-blended systems, such as mixing the polymer with graphene derivatives. In this study, we developed a polymer-graphene derivative complex with the chemical assistance of a surfactant (octadecylamine, ODA)...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28530404/role-of-crystallization-in-the-morphology-of-polymer-non-fullerene-acceptor-bulk-heterojunctions
#8
Kathryn A O'Hara, David P Ostrowski, Unsal Koldemir, Christopher J Takacs, Sean E Shaheen, Alan Sellinger, Michael L Chabinyc
Many high efficiency organic photovoltaics use fullerene-based acceptors despite their high production cost, weak optical absorption in the visible range, and limited synthetic variability of electronic and optical properties. To circumvent this deficiency, non-fullerene small-molecule acceptors have been developed that have good synthetic flexibility, allowing for precise tuning of optoelectronic properties, leading to enhanced absorption of the solar spectrum and increased open-circuit voltages (VOC). We examined the detailed morphology of bulk heterojunctions of poly(3-hexylthiophene) and the small-molecule acceptor HPI-BT to reveal structural changes that lead to improvements in the fill factor of solar cells upon thermal annealing...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28530277/advanced-microscopy-and-spectroscopy-reveal-the-adsorption-and-clustering-of-cu-ii-onto-tempo-oxidized-cellulose-nanofibers
#9
Chuantao Zhu, Alexander Soldatov, Aji P Mathew
TEMPO (2,2,6,6-tetramethylpiperidine-1-oxylradical)-mediated oxidation nanofibers (TOCNF), as a biocompatible and bioactive material, have opened up a new application of nanocellulose for the removal of water contaminants. This development demands extremely sensitive and accurate methods to understand the surface interactions between water pollutants and TOCNF. In this report, we investigated the adsorption of metal ions on TOCNF surfaces using experimental techniques atthe nano and molecular scales with Cu(ii) as the target pollutant in both aqueous and dry forms...
May 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/28530184/green-synthesis-of-silver-nanoparticles-using-mentha-pulegium-and-investigation-of-their-antibacterial-antifungal-and-anticancer-activity
#10
Ali Hamad Abd Kelkawi, Abolghasem Abbasi Kajani, Abdol-Khalegh Bordbar
A simple and eco-friendly method for efficient synthesis of stable colloidal silver nanoparticles (AgNPs) using Mentha pulegium extracts is described. A series of reactions was conducted using different types and concentrations of plant extract as well as metal ions to optimize the reaction conditions. AgNPs were characterized by using UV-vis spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering, zetasizer, energy-dispersive X-ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR)...
June 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28528632/clafem-correlative-light-atomic-force-electron-microscopy
#11
Sébastien Janel, Elisabeth Werkmeister, Antonino Bongiovanni, Frank Lafont, Nicolas Barois
Atomic force microscopy (AFM) is becoming increasingly used in the biology field. It can give highly accurate topography and biomechanical quantitative data, such as adhesion, elasticity, and viscosity, on living samples. Nowadays, correlative light electron microscopy is a must-have tool in the biology field that combines different microscopy techniques to spatially and temporally analyze the structure and function of a single sample. Here, we describe the combination of AFM with superresolution light microscopy and electron microscopy...
2017: Methods in Cell Biology
https://www.readbyqxmd.com/read/28528552/universal-selective-dispersion-of-semiconducting-carbon-nanotubes-from-commercial-sources-using-a-supramolecular-polymer
#12
Alex Chortos, Igor Pochorovski, Pei Lin, Gregory Pitner, Xuzhou Yan, Theodore Z Gao, John W F To, Ting Lei, John W Will, H-S Philip Wong, Zhenan Bao
Selective extraction of semiconducting carbon nanotubes is a key step in the production of high-performance, solution-processed electronics. Here we describe the ability of a supramolecular sorting polymer to selectively disperse semiconducting carbon nanotubes from five commercial sources with diameters ranging from 0.7 nm to 2.2 nm. The sorting purity of the largest diameter nanotubes (1.4 nm to 2.2 nm; from Tuball) was confirmed by short channel measurements to be 97.5%. Removing the sorting polymer by acid-induced disassembly increased the transistor mobility by 94% and 24% for medium-diameter and large-diameter carbon nanotubes, respectively...
May 21, 2017: ACS Nano
https://www.readbyqxmd.com/read/28527981/an-identification-of-the-soft-polyelectrolyte-gel-like-layer-on-silica-colloids-using-atomic-force-and-electron-microscopy
#13
Jiří Škvarla, Juraj Škvarla
A procedure is introduced for measuring the radius of spherical colloid particles from the curvature of upper parts of their central cross-sectional profiles obtained by atomic force microscopy (AFM). To minimize the possible compression and displacement of the spheres, AFM is operated in a mode rendering a constant ultralow pN force on the tip. The procedure allows us to evaluate the mean radius of nearly monodisperse submicrometer spheres of silica in their natively hydrated state in aqueous electrolyte solutions, irrespective of whether they are coagulated or not...
May 16, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28527974/the-effect-of-%C3%AE-sheet-breaker-peptides-on-metal-associated-amyloid-%C3%AE-peptide-aggregation-process
#14
F Stellato, Z Fusco, R Chiaraluce, V Consalvi, S Dinarelli, E Placidi, M Petrosino, G C Rossi, V Minicozzi, S Morante
Far-UV Circular Dichroism experiments and Atomic Force Microscopy tomography are employed to assess the impact of β-sheet breakers on the Aβ1-40 peptide aggregation process in the presence of Cu(2+) or Zn(2+) transition metals. In this work we focus on two specific 5-amino acids long β-sheet breakers, namely the LPFFD Soto peptide, already known in the literature, and the LPFFN peptide recently designed and studied by our team. We provide evidence that both β-sheet breakers are effective in reducing the Aβ1-40 aggregation propensity, even in the presence of metal ions...
May 15, 2017: Biophysical Chemistry
https://www.readbyqxmd.com/read/28526091/a-pre-therapeutic-coating-for-medical-devices-that-prevents-the-attachment-of-candida-albicans
#15
Diego Vargas-Blanco, Aung Lynn, Jonah Rosch, Rony Noreldin, Anthony Salerni, Christopher Lambert, Reeta P Rao
BACKGROUND: Hospital acquired fungal infections are defined as "never events"-medical errors that should never have happened. Systemic Candida albicans infections results in 30-50% mortality rates. Typically, adhesion to abiotic medical devices and implants initiates such infections. Efficient adhesion initiates formation of aggressive biofilms that are difficult to treat. Therefore, inhibitors of adhesion are important for drug development and likely to have a broad spectrum efficacy against many fungal pathogens...
May 19, 2017: Annals of Clinical Microbiology and Antimicrobials
https://www.readbyqxmd.com/read/28525820/sensing-inhomogeneous-mechanical-properties-of-human-corneal-descemet-s-membrane-with-afm-nano-indentation
#16
Rosa Di Mundo, Giuseppina Recchia, Mohit Parekh, Alessandro Ruzza, Stefano Ferrari, Giuseppe Carbone
The paper describes a highly space-resolved characterization of the surface mechanical properties of the posterior human corneal layer (Descemet's membrane). This has been accomplished with Atomic Force Microscopy (AFM) nano-indentation by using a probe with a sharp tip geometry. Results indicate that the contact with this biological tissue in liquid occurs with no (or very low) adhesion. More importantly, under the same operating conditions, a broad distribution of penetration depth can be measured on different x-y positions of the tissue surface, indicating a high inhomogeneity of surface stiffness, not yet clearly reported in the literature...
May 10, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28525394/modified-denatured-lysozyme-effectively-solubilizes-fullerene-c60-nanoparticles-in-water
#17
Marialuisa Siepi, Jane Politi, Principia Dardano, Angela Amoresano, Luca De Stefano, Daria Maria Monti, Eugenio Notomista
Fullerenes, allotropic forms of carbon, have very interesting pharmacological effects and engineering applications. However, a very low solubility both in organic solvents and water hinders their use. Fullerene C60, the most studied among fullerenes, can be dissolved in water only in the form of nanoparticles of variable dimensions and limited stability. Here the effect on the production of C60 nanoparticles by native and denatured hen egg white lysozyme, a highly basic protein, has been systematically studied...
May 19, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28524087/in-vitro-assessment-of-early-bacterial-activity-on-micro-nanostructured-ti6al4v-surfaces
#18
Benjamin Valdez-Salas, Ernesto Beltrán-Partida, Sandra Castillo-Uribe, Mario Curiel-Álvarez, Roumen Zlatev, Margarita Stoytcheva, Gisela Montero-Alpírez, Lidia Vargas-Osuna
It is imperative to understand and systematically compare the initial interactions between bacteria genre and surface properties. Thus, we fabricated a flat, anodized with 80 nm TiO₂ nanotubes (NTs), and a rough Ti6Al4V surface. The materials were characterized using field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). We cultured in vitro Staphylococcus epidermidis (S. epidermidis) and Pseudomonas aeruginosa (P. aeruginosa) to evaluate the bacterial-surface behavior by FE-SEM and viability calculation...
May 18, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28523651/microstructure-and-nanomechanical-properties-of-single-stalks-from-diatom-didymosphenia-geminata-and-their-change-due-to-adsorption-of-selected-metal-ions
#19
Izabela Zgłobicka, Adrian Chlanda, Michał Woźniak, Maciej Łojkowski, Robert Szoszkiewicz, Marta Mazurkiewicz-Pawlicka, Wojciech Święszkowski, Elżbieta Wyroba, Krzysztof J Kurzydłowski
We present topographical and nanomechanical characterization of single Didymosphenia geminata stalks. We compared the samples before and after adsorption of metal ions from fresh water samples. Transmission electron microscopy studies of single stalks cross-sections have shown three distinct layers and an additional thin extra coat on the external layer (called here "EL"). Using scanning electron microscopy and atomic force microscopy (AFM) we found that topography of single stalks after ionic adsorption differs significantly from topography of pristine stalks...
May 18, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28523613/eco-friendly-and-cost-effective-ag-nanocrystals-fabricated-using-the-leaf-extract-of-habenaria-plantaginea-toxicity-on-six-mosquito-vectors-and-four-non-target-species
#20
Chinnadurai Aarthi, Marimuthu Govindarajan, Pichaimuthu Rajaraman, Naiyf S Alharbi, Shine Kadaikunnan, Jamal M Khaled, Ramzi A Mothana, Nasir A Siddiqui, Giovanni Benelli
Recently, the biofabrication of metal nanoparticles has gained wide interest owing to its inherent features such as swift, simplicity, eco-friendliness, and cheaper costs. Different green-reducing agents led to the production of nanoparticles with varying toxicity on insects. In the current study, silver nanoparticles (AgNPs) were successfully synthesized using Habenaria plantaginea leaf extract. Ag nanoparticles were studied by UV-Vis spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM)...
May 18, 2017: Environmental Science and Pollution Research International
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