Atomic force microscopy probing of cell elasticity (original) (raw)
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Insights in Cell Biomechanics through Atomic Force Microscopy
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We review the advances obtained by using Atomic Force Microscopy (AFM)-based approaches in the field of cell/tissue mechanics and adhesion, comparing the solutions proposed and critically discussing them. AFM offers a wide range of detectable forces with a high force sensitivity, thus allowing a broad class of biological issues to be addressed. Furthermore, it allows for the accurate control of the probe position during the experiments, providing spatially resolved mechanical maps of the biological samples with subcellular resolution. Nowadays, mechanobiology is recognized as a subject of great relevance in biotechnological and biomedical fields. Focusing on the past decade, we discuss the intriguing issues of cellular mechanosensing, i.e., how cells sense and adapt to their mechanical environment. Next, we examine the relationship between cell mechanical properties and pathological states, focusing on cancer and neurodegenerative diseases. We show how AFM has contributed to the cha...
2000
The atomic force microscope (AFM) has become an increasingly useful tool for the life sciences. One of the great advantages of AFM is its ability to image and measure forces in living biological samples at subnanometer resolution in a physiologically stable environment. However, imaging living cells can be extremely challenging and requires consideration of sample preparation methods and stabilisation of
Journal of Microbiological Methods, 2011
Atomic force microscopy (AFM) is a technique that has long been employed in materials science, but is now increasingly being used in the biological sciences. AFM provides excellent topographical information on prokaryotic and eukaryotic cell surfaces, and the extracellular material produced by the cells. It helps to generate important data on the mechanical properties of cells, such as hardness and elasticity. AFM can also be used to measure the strength of adhesion, attraction, and repulsion forces between cells and surfaces or even between individual molecules. Additionally, by combining AFM with other complementary techniques such as fluorescence microscopy or Raman spectroscopy, the chemistry of given surface structures can be identified. This review aims to provide an update on the AFM techniques currently used in cell biology studies, along with a description of the range of recently developed research methodologies in which AFM plays a key role.
Characterization of cell elasticity correlated with cell morphology by atomic force microscope
Journal of Biomechanics, 2012
Biomechanical properties of cells have been identified as an important factor in a broad range of biological processes. Based on measurements of mechanical properties by atomic force microscopy (AFM) particularly cell elasticity has been linked with human diseases, such as cancer. AFM has been widely used as a nanomechanical tool to probe the elasticity of living cells, however, standard methods for characterizing cell elasticity are still lacking. The local elasticity of a cell is conventionally used to represent the mechanical property of the cell. However, since cells have highly heterogeneous regions, elasticity mapping over the entire cell, rather than at a few points of measurement, is required. Using human aortic endothelial cells (HAECs) as a model, we have developed in this study a new method to evaluate cell elasticity more quantitatively. Based on the height information of the cell, a new characterization method was proposed to evaluate the elasticity of a cell. Using this method, elasticities of cells on different substrates were compared. Results showed that the elasticity of HAECs on softer substrate also has higher value compared to those on harder substrate given a certain height where the statistical distribution analysis confirmed that higher actin filaments density was located. Thus, the elasticity of small portions of a cell could not represent the entire cell property and may lead to invalid characterization. In order to gain a more comprehensive and detailed understanding of biomechanical properties for future clinical use, elasticity and cell morphology should therefore be correlated with discussion.
Looking at cell mechanics with atomic force microscopy: Experiment and theory
Microscopy Research and Technique, 2014
This review reports on the use of the atomic force microscopy in the investigation of the mechanical properties of cells. It is shown that the technique is able to deliver information about the cell surface properties (e.g., topography), the Young modulus, the viscosity, and the cell the relaxation times. Another aspect that this short review points out is the utilization of the atomic force microscope to investigate basic questions related to materials physics, biology, and medicine. The review is written in a chronological way to offer an overview of phenomenological facts and quantitative results to the reader. The final section discusses in detail the advantages and disadvantages of the Hertz and JKR models. A new implementation of the JKR model derived by Dufresne is presented.
Influencing Factors in Atomic Force Microscopy Based Mechanical Characterization of Biological Cells
Experimental Techniques, 2017
AFM-based single cell force spectroscopy is increasingly being used to understand many biological health problems like malaria, cancer etc. A reliable diagnostics needs, accurate measurement and a clear understanding of the influencing factors, which may otherwise sour the measured biomechanics. Results from any successful experimentation should be repeatable and error free. For this, a deeper understanding of the sources of uncertainties, which may affect the results is necessary. In order to assure the accuracy of evaluated properties and to avoid misinterpretation of the experimental data, we have categorized the common causes of uncertainties in an AFM force spectroscopy, based on their sources of origin and discussed possible remedies to them. The present work discusses the assumptions involved in AFM-based biomechanical studies (assumptions in contact model, data analysis, instrument calibration etc.) and their implications in overall estimations of mechanical biomarkers like stiffness, and adhesive strength. Advantages and disadvantages of simultaneous measurement of stiffness and adhesiveness from single force-indentation data have also been discussed.
Feeling the forces: atomic force microscopy in cell biology
Life Sciences, 2003
Atomic force microscopy allows three-dimensional imaging and measurements of unstained and uncoated biological samples in air or fluid. Using this technology it offers resolution on the nanometer scale and detection of temporal changes in the mechanical properties, i.e. surface stiffness or elasticity in live cells and membranes. Various biological processes including ligand-receptor interactions, reorganization, and restructuring of the cytoskeleton associated with cell motility that are governed by intermolecular forces and their mode of detection will be discussed. D
Relative Microelastic Mapping of Living Cells by Atomic Force Microscopy
Biophysical Journal, 1998
The spatial and temporal changes of the mechanical properties of living cells reflect complex underlying physiological processes. Following these changes should provide valuable insight into the biological importance of cellular mechanics and their regulation. The tip of an atomic force microscope (AFM) can be used to indent soft samples, and the force versus indentation measurement provides information about the local viscoelasticity. By collecting force-distance curves on a time scale where viscous contributions are small, the forces measured are dominated by the elastic properties of the sample. We have developed an experimental approach, using atomic force microscopy, called force integration to equal limits (FIEL) mapping, to produce robust, internally quantitative maps of relative elasticity. FIEL mapping has the advantage of essentially being independent of the tip-sample contact point and the cantilever spring constant. FIEL maps of living Madine-Darby canine kidney (MDCK) cells show that elasticity is uncoupled from topography and reveal a number of unexpected features. These results present a mode of high-resolution visualization in which the contrast is based on the mechanical properties of the sample.