scholarly journals The Effect of Ethanol on Disassembly of Amyloid-β1-42 Pentamer Revealed by Atomic Force Microscopy and Gel Electrophoresis

2022 ◽  
Vol 23 (2) ◽  
pp. 889
Author(s):  
Atsuya Matsui ◽  
Jean-Pierre Bellier ◽  
Takeshi Kanai ◽  
Hiroki Satooka ◽  
Akio Nakanishi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Quantitative Estimation ◽  
Senile Plaques ◽  
Protein Structures ◽  
Amyloid Β ◽  
Ambient Air ◽  
Native Page ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Impact

The most common type of dementia, Alzheimer’s disease, is associated with senile plaques formed by the filamentous aggregation of hydrophobic amyloid-β (Aβ) in the brains of patients. Small oligomeric assemblies also occur and drugs and chemical compounds that can interact with such assemblies have attracted much attention. However, these compounds need to be solubilized in appropriate solvents, such as ethanol, which may also destabilize their protein structures. As the impact of ethanol on oligomeric Aβ assembly is unknown, we investigated the effect of various concentrations of ethanol (0 to 7.2 M) on Aβ pentameric assemblies (Aβp) by combining blue native-PAGE (BN-PAGE) and ambient air atomic force microscopy (AFM). This approach was proven to be very convenient and reliable for the quantitative analysis of Aβ assembly. The Gaussian analysis of the height histogram obtained from the AFM images was correlated with band intensity on BN-PAGE for the quantitative estimation of Aβp. Our observations indicated up to 1.4 M (8.3%) of added ethanol can be used as a solvent/vehicle without quantitatively affecting Aβ pentamer stability. Higher concentration induced significant destabilization of Aβp and eventually resulted in the complete disassembly of Aβp.

Protective Coating Based on Organic Silicon Polymer of Ladder Structure Nanostructured with Alkoxysilane

2020 ◽  
Vol 992 ◽  
pp. 580-584
Author(s):  
V.Yu. Chukhlanov ◽  
O.G. Selivanov ◽  
N.V. Chukhlanova
Keyword(s):  
Atomic Force Microscopy ◽  
Physical Properties ◽  
Protective Coating ◽  
Silicon Oxide ◽  
Polymer Composition ◽  
Orthosilicic Acid ◽  
Force Microscopy ◽  
Atomic Force ◽  
Destruction Kinetics ◽  
The Impact

New materials based on oligooxidridsilmethylensiloxysilane nanostructured with ethyl ester of orthosilicic acid – tetraethoxysilane have been studied in the research. Tetraethoxysilane introduction into the composition is supposed to cause its decomposition up to nanoparticles of silicon oxide. The alkoxysilane hydrolytic destruction kinetics and the impact of the composition and nature of the polymer composition components on the physical properties have been studied. Atomic force microscopy was used to study the structurization kinetics of the polymer composition. The composition hydrophobicity was determined by the edge wetting angle. To study the adhesion characteristics of the obtained material, the method of disc separation from the substrate has been used. The relative rigidity has been determined by a pendulum device M3. Atomic force microscopy revealed the presence of nanoscale neoplasms (at average of one hundred twenty per one square micrometer) in diameter from two to five nanometers in the surface structure of the composition, modified with tetraethoxysilane. Herewith the physical properties of the material change: rigidity increases, the edge angle of wetting increases as well. The studied nanostructured compositions can also be applied. For example – they can be used as a protective coating with a set of special properties, such as high hydrophobicity.

scholarly journals Characterisation of InGaN by Photoconductive Atomic Force Microscopy

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1794 ◽  
Author(s):  
Thomas Weatherley ◽  
Fabien Massabuau ◽  
Menno Kappers ◽  
Rachel Oliver
Keyword(s):  
Atomic Force Microscopy ◽  
Cross Sections ◽  
Indium Content ◽  
Light Emitting ◽  
Force Microscopy ◽  
Turn On ◽  
Atomic Force ◽  
Voltage Curve ◽  
Current Voltage Curve ◽  
The Impact

Nanoscale structure has a large effect on the optoelectronic properties of InGaN, a material vital for energy saving technologies such as light emitting diodes. Photoconductive atomic force microscopy (PC-AFM) provides a new way to investigate this effect. In this study, PC-AFM was used to characterise four thick (∼130 nm) In x Ga 1 − x N films with x = 5%, 9%, 12%, and 15%. Lower photocurrent was observed on elevated ridges around defects (such as V-pits) in the films with x ≤ 12 %. Current-voltage curve analysis using the PC-AFM setup showed that this was due to a higher turn-on voltage on these ridges compared to surrounding material. To further understand this phenomenon, V-pit cross sections from the 9% and 15% films were characterised using transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. This identified a subsurface indium-deficient region surrounding the V-pit in the lower indium content film, which was not present in the 15% sample. Although this cannot directly explain the impact of ridges on turn-on voltage, it is likely to be related. Overall, the data presented here demonstrate the potential of PC-AFM in the field of III-nitride semiconductors.

scholarly journals Nanoscale Dynamics of Amyloid β-42 Oligomers As Revealed by High-Speed Atomic Force Microscopy

ACS Nano ◽  
2017 ◽  
Vol 11 (12) ◽  
pp. 12202-12209 ◽  
Author(s):  
Siddhartha Banerjee ◽  
Zhiqiang Sun ◽  
Eric Y. Hayden ◽  
David B. Teplow ◽  
Yuri L. Lyubchenko
Keyword(s):  
Atomic Force Microscopy ◽  
High Speed ◽  
Amyloid Β ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nanoscale Dynamics

Imidazolium-Based Ionic Liquids Affect Morphology and Rigidity of Living Cells: an Atomic Force Microscopy Study

2018 ◽  
Author(s):  
Massimiliano Galluzzi ◽  
Carsten Schulte ◽  
Paolo Milani ◽  
Alessandro Podestà
Keyword(s):  
Atomic Force Microscopy ◽  
Ionic Liquids ◽  
Cell Membrane ◽  
Molecular Mechanisms ◽  
Single Cells ◽  
Metastatic Cancer ◽  
Toxic Effects ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Impact

The study of the toxicity, biocompatibility, and environmental sustainability of room-temperature Ionic Liquids (ILs) is still in its infancy. Understanding the impact of ILs on living organisms, especially from the aquatic ecosystem, is urgent, since on one side large amounts of these substances are widely employed as solvents in industrial chemical processes, and on the other side evidences of toxic effects of ILs on microorganisms and single cells have been observed. To date, the toxicity of ILs have been investigated by means of macroscopic assays aimed at characterizing the effective concentrations (like the EC50) that cause the dead of a significant fraction of the population of microorganisms and cells. These studies allowed to identify the cell membrane as the first target of the IL interaction, whose effectiveness was correlated to the lipophilicity of the cation, i.e. to the length of the lateral alkyl chain. Our study aimed at characterizing the molecular mechanisms of the toxicity of ILs. To this purpose, we carried out a combined topographic and mechanical analysis by Atomic Force Microscopy of living breast metastatic cancer cells (MDA-MB-231) upon interaction with imidazolium-based ILs. We showed that ILs are able to induce modifications of the overall rigidity (effective Young modulus) and morphology of the cells. Our results demonstrate that ILs act on the physical properties of the cell membrane, and possibly induce cytoskeletal reorganization, already at concentrations below the EC50. These potentially toxic effects are stronger at higher IL concentrations, as well as with longer lateral chains in the cation.<br>

Probing Amyloid β and the Antibody Interaction Using Atomic Force Microscopy

2018 ◽  
Vol 18 (2) ◽  
pp. 1410-1413 ◽  
Author(s):  
Sung-Woong Han ◽  
Tae-Hoon Lee ◽  
Min-Sik Kang ◽  
Hyung Jin Kim ◽  
Hoon-Kyu Shin
Keyword(s):  
Atomic Force Microscopy ◽  
Amyloid Β ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Assessment of Elasticity and Topography of Aspergillus nidulans Spores via Atomic Force Microscopy

2005 ◽  
Vol 71 (2) ◽  
pp. 955-960 ◽  
Author(s):  
Liming Zhao ◽  
David Schaefer ◽  
Mark R. Marten
Keyword(s):  
Atomic Force Microscopy ◽  
Aspergillus Nidulans ◽  
Fungal Spores ◽  
Protein Structures ◽  
Spore Surface ◽  
Wild Type ◽  
Adhesive Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Tapping Mode Afm

ABSTRACT Previous studies have described both surface morphology and adhesive properties of fungal spores, but little information is currently available on their mechanical properties. In this study, atomic force microscopy (AFM) was used to investigate both surface topography and micromechanical properties of Aspergillus nidulans spores. To assess the influence of proteins covering the spore surface, wild-type spores were compared with spores from isogenic rodA + and rodA − strains. Tapping-mode AFM images of wild-type and rodA + spores in air showed characteristic “rodlet” protein structures covering a granular spore surface. In comparison, rodA − spores were rodlet free but showed a granular surface structure similar to that of the wild-type and rodA + spores. Rodlets were removed from rodA + spores by sonication, uncovering the underlying granular layer. Both rodlet-covered and rodlet-free spores were subjected to nanoindentation measurements, conducted in air, which showed the stiffnesses to be 110 ± 10, 120 ± 10, and 300 ± 20 N/m and the elastic moduli to be 6.6 ± 0.4, 7.0 ± 0.7, and 22 ± 2 GPa for wild-type, rodA + and rodA − spores, respectively. These results imply the rodlet layer is significantly softer than the underlying portion of the cell wall.

scholarly journals High-Speed Atomic Force Microscopy Reveals the Structural Dynamics of the Amyloid-β and Amylin Aggregation Pathways

2020 ◽  
Vol 21 (12) ◽  
pp. 4287
Author(s):  
Takahiro Watanabe-Nakayama ◽  
Bikash R. Sahoo ◽  
Ayyalusamy Ramamoorthy ◽  
Kenjiro Ono
Keyword(s):  
Atomic Force Microscopy ◽  
Protein Structure ◽  
Real Time ◽  
Structural Dynamics ◽  
High Speed ◽  
Amyloid Β ◽  
Force Microscopy ◽  
Structure And Dynamics ◽  
Atomic Force ◽  
Novel Therapeutic Strategies

Individual Alzheimer’s disease (AD) patients have been shown to have structurally distinct amyloid-β (Aβ) aggregates, including fibrils, in their brain. These findings suggest the possibility of a relationship between AD progression and Aβ fibril structures. Thus, the characterization of the structural dynamics of Aβ could aid the development of novel therapeutic strategies and diagnosis. Protein structure and dynamics have typically been studied separately. Most of the commonly used biophysical approaches are limited in providing substantial details regarding the combination of both structure and dynamics. On the other hand, high-speed atomic force microscopy (HS-AFM), which simultaneously visualizes an individual protein structure and its dynamics in liquid in real time, can uniquely link the structure and the kinetic details, and it can also unveil novel insights. Although amyloidogenic proteins generate heterogeneously aggregated species, including transient unstable states during the aggregation process, HS-AFM elucidated the structural dynamics of individual aggregates in real time in liquid without purification and isolation. Here, we review and discuss the HS-AFM imaging of amyloid aggregation and strategies to optimize the experiments showing findings from Aβ and amylin, which is associated with type II diabetes, shares some common biological features with Aβ, and is reported to be involved in AD.

scholarly journals Elucidating nanoscale mechanical properties of diabetic human adipose tissue using atomic force microscopy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
J. K. Wenderott ◽  
Carmen G. Flesher ◽  
Nicki A. Baker ◽  
Christopher K. Neeley ◽  
Oliver A. Varban ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Metabolic Disease ◽  
Atomic Force Microscopy ◽  
Adipose Tissue ◽  
Elastic Modulus ◽  
Tissue Mechanics ◽  
Health Concern ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Impact

AbstractObesity-related type 2 diabetes (DM) is a major public health concern. Adipose tissue metabolic dysfunction, including fibrosis, plays a central role in DM pathogenesis. Obesity is associated with changes in adipose tissue extracellular matrix (ECM), but the impact of these changes on adipose tissue mechanics and their role in metabolic disease is poorly defined. This study utilized atomic force microscopy (AFM) to quantify difference in elasticity between human DM and non-diabetic (NDM) visceral adipose tissue. The mean elastic modulus of DM adipose tissue was twice that of NDM adipose tissue (11.50 kPa vs. 4.48 kPa) to a 95% confidence level, with significant variability in elasticity of DM compared to NDM adipose tissue. Histologic and chemical measures of fibrosis revealed increased hydroxyproline content in DM adipose tissue, but no difference in Sirius Red staining between DM and NDM tissues. These findings support the hypothesis that fibrosis, evidenced by increased elastic modulus, is enhanced in DM adipose tissue, and suggest that measures of tissue mechanics may better resolve disease-specific differences in adipose tissue fibrosis compared with histologic measures. These data demonstrate the power of AFM nanoindentation to probe tissue mechanics, and delineate the impact of metabolic disease on the mechanical properties of adipose tissue.

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