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Abstract: Myotonic Dystrophy type 1 (DM1) is the most common form of muscular dystrophy in adults, characterized by a variety of multisystemic features and associated with cardiac anomalies. Among cardiac phenomena, conduction defects, ventricular arrhythmias, and dilated cardiomyopathy represent the main cause of sudden death in DM1 patients. Patient‐specific induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs) represent a powerful in vitro model for molecular, biochemical, and physiological studies of disease in the target cells. Here, we used an Atomic Force Microscope (AFM) to measure the beating profiles of a large number of cells, organized in CM clusters (Beating Bodies, BBs), obtained from wild type (WT) and DM1 patients. We monitored the evolution over time of the frequency and intensity of the beating. We determined the variations between different BBs and over various areas of a single BB, caused by morphological and biomechanical variations. We exploited the AFM tip to apply a controlled force over the BBs, to carefully assess the biomechanical reaction of the different cell clusters over time, both in terms of beating frequency and intensity. Our measurements demonstrated differences between the WT and DM1 clusters highlighting, for the DM1 samples, an instability which was not observed in WT cells. We measured differences in the cellular response to the applied mechanical stimulus in terms of beating synchronicity over time and cell tenacity, which are in good agreement with the cellular behavior in vivo. Overall, the combination of hiPSC‐CMs with AFM characterization can become a new tool to study the collective movements of cell clusters in different conditions and can be extended to the characterization of the BB response to chemical and pharmacological stimuli. [ABSTRACT FROM AUTHOR]

The study of the mechanical properties of biosystems and the relationship with their biochemical and structural functionality is an increasingly interesting subject of investigation. In recent years, in particular, the use of the atomic force microscopy provides the tools for understanding the molecular basis of the mechanical behaviour of the biosystems. The ageing of erythrocytes [red blood cells (RBCs)] constitutes a particularly interesting subject of study because of its fundamental role in triggering the cell turnover by promoting the removal of malfunctioning RBCs when specific ageing markers appear on their surface. Moreover, it is also interesting to study the role that the variation in the cells mechanical properties plays in the progress of the phenomenon. In this study, the ageing of RBCs, accelerated by depleting the cells of their ATP, has been investigated by two methods. The first is a recently developed nondestructive approach that correlates the roughness of the plasma membrane to the mechanical characteristics and the structural integrity of the cell membrane-skeleton. The second consists in directly measuring the nanomechanical properties by acquiring and analysing force curves on the cell membrane. The application of the two methods allowed to define, for the first time, the general scheme of alterations the cells experience during the ageing. In particular, a progressive decrease of the membrane roughness, correlated to a weakening of the membrane-skeleton support, and a complex pattern of changes in the nanomechanical properties, which drives the morphological variation and the occurrence of the specific ageing markers on the cells, have been revealed. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study is to investigate the nanocrystallization of steels caused by the transformation from the austenitic to the martensitic phase induced by a severe plastic deformation (SPD) treatment. In this framework, we applied an air blast shot peening treatment, which is a simple protocol widely used for industrial purposes. Methods: AISI 286 and AISI 316 specimens were peened for different times and polished using diamond pastes in order to remove corrugations higher than 1 μm. The characterization of the steel surfaces was performed by atomic force microscopy (AFM) operating in contact mode. Additional EDXD measurements were performed to confirm the phase transition. Results and Discussion: An AFM-based characterization at nanometric level of the steel surfaces is provided. When the peening exceeds a threshold time that, as expected, depends on the steel composition, a uniform nanostructuration is detected. It is well known that such rearrangement is associated to the growth of a martensitic phase. To date, AFM has been employed in this field only for few applications and to solve specific problems. On the other hand, our results demonstrate that this is a useful technique for the characterization of hardened surfaces, especially when non-destructive sample preparation treatments are required. Moreover, we show that AFM can be a useful tool also for in situ industrial diagnostics of metallic parts. [ABSTRACT FROM AUTHOR]

We present the implementation of a tapping-mode aperture scanning near-field optical microscope (Tapping-SNOM) to a Binder CB incubator (Istituto di Struttura della Materia, Rome, Italy). The microscope operates in the intermittent contact mode using a nonbent optical fibre allowing to reduce the perturbation exerted on the sample, while the incubator maintains a constant temperature, humidity and CO2 level. This instrument can maintain and analyse in a controlled environment different samples, both organic and nonorganic. In particular, the Tapping-SNOM can study different cell lines at nanometric resolution and in physiological buffer, following the evolution of the living cells almost indefinitely. We will present several examples of the capabilities of the tapping scanning near-field optical microscope in the study of different lines of living cells, showing corresponding topographical, optical or phase-lag images of the live samples, evidencing the excellent stability, versatility and resolution of the system. [ABSTRACT FROM AUTHOR]

We used air operating atomic force microscopy (AFM) to study several morphological modifications of human erythrocytes, artificially produced by addition of exogenous agents including phospholipids, low ionic strength media and drugs. Most experiments were performed on unfixed samples to avoid treating red blood cells (RBCs) with chemical agents that can, in principle, induce morphological alteration. After detailed quantitative AFM characterization, the artificially produced abnormally shaped RBCs were compared with cells that occur with high incidence in blood pathologies. This morphological approach suggests a new strategy to describe and understand the biochemical and/or mechanical modifications responsible for the underlying pathologically induced changes and prove AFM to be a suitable tool to study erythrocyte deformation. [ABSTRACT FROM AUTHOR]

Erythrocytes (RBCs) constitute a very interesting class of cells both for their physiological function and for a variety of peculiarities. Due to their exceptionally strong relationship with the environment, the morphology and nanoscale characteristics of these cells can reveal their biochemical status and structural integrity. Among the possible subjects of investigations, the RBCs' ageing is of the utmost importance. This is a fundamental phenomenon that, in physiological conditions, triggers the cell turnover and ensures the blood homeostasis. With these premises, in recent years, we have presented an atomic force microscopy–based methodology to characterize the patterns of RBC ageing from the morphological point of view. In the present work, we used an ageing protocol more similar to the physiological conditions and we used differential scanning calorimetry and atomic force microscopy to probe the cross correlation between important structural and functional proteins. We also assessed the role played by fundamental structural and membrane proteins in the development of the most relevant morphological intermediates observed along the ageing. Furthermore, we coupled the morphological ageing patterns to the (bio)chemical alterations detected by Raman spectroscopy. This allowed identifying the chronology of the ageing morphologies and the metabolic pathways most involved in their development. As a whole, the present study provides the base to correlate specific molecular alterations to the development of structural anomalies, and these latter to the functional status of blood cells. We characterized the pattern of erythrocytes' ageing in starvation conditions through an experimental approach that combined atomic force microscopy (AFM), differential scanning calorimetry (DSC), and Raman spectro‐microscopy. Moreover, by using a DSC‐based procedure consisting in the warming and chilling of the samples at specific temperature capable to induce unfolding of specific cytoskeletal proteins, we were able to understand the role of selected molecular components in the development of structural anomalies and in the induction of specific ageing‐related morphologies. [ABSTRACT FROM AUTHOR]