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

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>

Cell penetration efficiency analysis of different atomic force microscopy nanoneedles into living cells

Scientific Reports ◽

10.1038/s41598-021-87319-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marcos Penedo ◽

Tetsuya Shirokawa ◽

Mohammad Shahidul Alam ◽

Keisuke Miyazawa ◽

Takehiko Ichikawa ◽

...

Keyword(s):

Atomic Force Microscopy ◽

Cell Membrane ◽

Cell Biology ◽

Cell Damage ◽

Efficiency Analysis ◽

Living Cells ◽

Biomolecular Recognition ◽

Cell Penetration ◽

Force Microscopy ◽

AbstractOver the last decade, nanoneedle-based systems have demonstrated to be extremely useful in cell biology. They can be used as nanotools for drug delivery, biosensing or biomolecular recognition inside cells; or they can be employed to select and sort in parallel a large number of living cells. When using these nanoprobes, the most important requirement is to minimize the cell damage, reducing the forces and indentation lengths needed to penetrate the cell membrane. This is normally achieved by reducing the diameter of the nanoneedles. However, several studies have shown that nanoneedles with a flat tip display lower penetration forces and indentation lengths. In this work, we have tested different nanoneedle shapes and diameters to reduce the force and the indentation length needed to penetrate the cell membrane, demonstrating that ultra-thin and sharp nanoprobes can further reduce them, consequently minimizing the cell damage.

Change in the Number Distribution of Complex Shear Modulus of Single Cells by Actin Cytoskeleton Modifications Measured by Atomic Force Microscopy

Biophysical Journal ◽

10.1016/j.bpj.2010.12.1106 ◽

2011 ◽

Vol 100 (3) ◽

pp. 163a

Author(s):

PingGen Cai ◽

Yusuke Mizutani ◽

Masahiro Tsuchiya ◽

Koichi Kawahara ◽

Takaharu Okajima

Keyword(s):

Atomic Force Microscopy ◽

Shear Modulus ◽

Actin Cytoskeleton ◽

Single Cells ◽

Complex Shear Modulus ◽

Force Microscopy ◽

Atomic Force ◽

Number Distribution ◽

Complex Shear

The method of minimizing the impact of local residual electrostatic charge on dimensional measurement accuracy in atomic force microscopy measurements

Measurement Science and Technology ◽

10.1088/0957-0233/22/9/094022 ◽

2011 ◽

Vol 22 (9) ◽

pp. 094022 ◽

Cited By ~ 2

Author(s):

Andrzej Sikora

Keyword(s):

Atomic Force Microscopy ◽

Measurement Accuracy ◽

Electrostatic Charge ◽

Force Microscopy ◽

Dimensional Measurement ◽

Dimensional Measurement Accuracy ◽

Atomic Force ◽

Size-Dependent Intercalation of Ions into Highly Oriented Pyrolytic Graphite in Ionic Liquids: An Electrochemical Atomic Force Microscopy Study

The Journal of Physical Chemistry C ◽

10.1021/jp203833v ◽

2011 ◽

Vol 115 (35) ◽

pp. 17429-17439 ◽

Cited By ~ 10

Author(s):

Pankaj R. Singh ◽

Xiangqun Zeng

Keyword(s):

Atomic Force Microscopy ◽

Ionic Liquids ◽

Pyrolytic Graphite ◽

Microscopy Study ◽

Highly Oriented Pyrolytic Graphite ◽

Atomic Force Microscopy Study ◽

Force Microscopy ◽

Size Dependent ◽

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

Langmuir ◽

10.1021/acs.langmuir.8b01554 ◽

2018 ◽

Vol 34 (41) ◽

pp. 12452-12462 ◽

Cited By ~ 7

Author(s):

Massimiliano Galluzzi ◽

Carsten Schulte ◽

Paolo Milani ◽

Alessandro Podestà

Keyword(s):

Atomic Force Microscopy ◽

Ionic Liquids ◽

Microscopy Study ◽

Living Cells ◽

Atomic Force Microscopy Study ◽

Force Microscopy ◽

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.992.580 ◽

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 ◽

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.

Characterisation of InGaN by Photoconductive Atomic Force Microscopy

Materials ◽

10.3390/ma11101794 ◽

2018 ◽

Vol 11 (10) ◽

pp. 1794 ◽

Cited By ~ 2

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 ◽

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.

Improved unroofing protocols for cryo-electron microscopy, atomic force microscopy and freeze-etching electron microscopy and the associated mechanisms

Microscopy ◽

10.1093/jmicro/dfaa028 ◽

2020 ◽

Vol 69 (6) ◽

pp. 350-359

Author(s):

Nobuhiro Morone ◽

Eiji Usukura ◽

Akihiro Narita ◽

Jiro Usukura

Keyword(s):

Electron Microscopy ◽

Atomic Force Microscopy ◽

Cell Membrane ◽

Apical Cell ◽

Force Microscopy ◽

Atomic Force ◽

Cryo Electron Microscopy ◽

Cytoplasmic Surface ◽

A Cell ◽

Freeze Etching

Abstract Unroofing, which is the mechanical shearing of a cell to expose the cytoplasmic surface of the cell membrane, is a unique preparation method that allows membrane cytoskeletons to be observed by cryo-electron microscopy, atomic force microscopy, freeze-etching electron microscopy and other methods. Ultrasound and adhesion have been known to mechanically unroof cells. In this study, unroofing using these two means was denoted sonication unroofing and adhesion unroofing, respectively. We clarified the mechanisms by which cell membranes are removed in these unroofing procedures and established efficient protocols for each based on the mechanisms. In sonication unroofing, fine bubbles generated by sonication adhered electrostatically to apical cell surfaces and then removed the apical (dorsal) cell membrane with the assistance of buoyancy and water flow. The cytoplasmic surface of the ventral cell membrane remaining on the grids became observable by this method. In adhesion unroofing, grids charged positively by coating with Alcian blue were pressed onto the cells, thereby tightly adsorbing the dorsal cell membrane. Subsequently, a part of the cell membrane strongly adhered to the grids was peeled from the cells and transferred onto the grids when the grids were lifted. This method thus allowed the visualization of the cytoplasmic surface of the dorsal cell membrane. This paper describes robust, improved protocols for the two unroofing methods in detail. In addition, micro-unroofing (perforation) likely due to nanobubbles is introduced as a new method to make cells transparent to electron beams.

Biological Atomic Force Microscopy for Imaging Gold-Labeled Liposomes on Human Coronary Artery Endothelial Cells

Journal of Pharmaceutics ◽

10.1155/2013/875906 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Ana-María Zaske ◽

Delia Danila ◽

Michael C. Queen ◽

Eva Golunski ◽

Jodie L. Conyers

Keyword(s):

Atomic Force Microscopy ◽

Endothelial Cells ◽

Coronary Artery ◽

Cell Membrane ◽

Fluorescent Microscopy ◽

Human Coronary Artery ◽

Force Microscopy ◽

Cell Internalization ◽

Although atomic force microscopy (AFM) has been used extensively to characterize cell membrane structure and cellular processes such as endocytosis and exocytosis, the corrugated surface of the cell membrane hinders the visualization of extracellular entities, such as liposomes, that may interact with the cell. To overcome this barrier, we used 90 nm nanogold particles to label FITC liposomes and monitor their endocytosis on human coronary artery endothelial cells (HCAECs) in vitro. We were able to study the internalization process of gold-coupled liposomes on endothelial cells, by using AFM. We found that the gold-liposomes attached to the HCAEC cell membrane during the first 15–30 min of incubation, liposome cell internalization occurred from 30 to 60 min, and most of the gold-labeled liposomes had invaginated after 2 hr of incubation. Liposomal uptake took place most commonly at the periphery of the nuclear zone. Dynasore monohydrate, an inhibitor of endocytosis, obstructed the internalization of the gold-liposomes. This study showed the versatility of the AFM technique, combined with fluorescent microscopy, for investigating liposome uptake by endothelial cells. The 90 nm colloidal gold nanoparticles proved to be a noninvasive contrast agent that efficiently improves AFM imaging during the investigation of biological nanoprocesses.