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Atomic force microscope (AFM) has been increasingly used throughout the last decade in the study of cell biology.
Beyond its effectiveness in high-resolution imaging, AFM also offers distinctive abilities for probing the various qualities of living cells in culture and, more specifically, mapping the spatial distribution of cell mechanical qualities. This type of work has provided a multitude of details on the frameworks and functions of the cytoskeleton and cell organelles.
AFM studies have significantly increased our knowledge of cell mechanics in normal and diseased states and offered glimpses forward in the study of disease pathophysiology AFM has also enabled the establishment of unique diagnostic and treatment options.
The mechanical qualities of cells studies under AFM include stiffness, anisotropy, and heterogeneity. The techniques are also used to examine multiple functional aspects of these qualities, including how they are affected by the cytoskeleton and cell organelles. Without a doubt, cell mechanical qualities have been found to significantly affect multiple crucial cell functions, like shape, flexibility, and mobility.
Furthermore, modifications to cell mechanical qualities have recently been linked to specific diseases like cancer and arthritis.
AFM as a Gamechanger
After its debut in 1986 as a high-resolution imaging tool, AFM has quickly become a popular technique for investigating cell biology, typically by studying the mechanical qualities of living cells in culture.
AFM is a technique with distinctive advantages for examining cell mechanics: It can examine with high degrees of sensitivity and spatial resolution. It also has the capability to be used for real-time measurements in a cell culture. Furthermore, AFM allows for the nanoindentation of living cells. This technique has allowed researchers to directly connect local mechanical qualities with cytoskeletal structures.
Examining Cell Mechanics with AFM
In addition to imaging surface topography, AFM can also chart the elastic qualities of living cells, which has produced interesting insights into many physiologic cell functions. Multiple analyses have used AFM in the analysis of mechanical qualities of various cell types, like fibroblasts and vertebrate cells. AFM can even evaluate different regions inside the same cell and under many different conditions.
Cell mechanics are a critical indication of cytoskeletal structure and function. Specifically, actin stress fibers are vital linear structures composed of actin and myosin that offer a contractile ability in many non-muscle cell types, and some vascular endothelial cells. AFM mapping research has revealed that these structures are very rigid compared to any other cellular structures. Taken together with the growing body of information relating cell mechanical qualities to cytoskeletal structure and substrate adhesion, these scientific studies emphasize the great potential for AFM elastography of living cells to offer novel biomechanical markers that will strengthen the detection, analysis, and treatment of disease.
Of specific interest is the rapidly-growing body of research that demonstrates a close link between cell mechanical qualities and certain disease conditions. For instance, cultured myotubes from a rat model of Duchenne muscular dystrophy were only one-fourth as rigid as normal cells, and recent evidence has indicated that some muscles are protected from this condition by upregulating specialized proteins that maintain cell stiffness. In osteoarthritis, cartilage chondrocytes display elevated viscoelastic moduli compared to healthy cells, which may be the reason behind the dissimilar reactions of these cells to mechanical stimulation.
More information on the mechanical qualities of various cell types is needed to establish standards and guidelines for contrasting mechanical qualities with those of a normal population. Furthermore, the creation of tools for dependable and fast characterization of cell mechanical qualities is crucial moving forward.
Finally, there is significant interest in the usage of AFM to examine the morphological and functional qualities of various microorganisms, leading to the creation of so-called “nanomicrobiology’.
Sources and Further Reading