Mapping stress inside living cells by atomic force microscopy in response to environmental stimuli

Microtubules Disruption Alters the Cellular Structures and Mechanics Depending on Underlying Chemical Cues

The extracellular matrix determines cell morphology and stiffness by manipulating the cytoskeleton. The impacts of extracellular matrix cues, including the mechanical and topographical cues on microtubules and their role in biological behaviors, are previously studied. However, there is a lack of understanding about how microtubules (MTs) are affected by environmental chemical cues, such as extracellular matrix density. Specifically, it is crucial to understand the connection between cellular morphology and mechanics induced by chemical cues and the role of microtubules in these cellular responses. To address this, surfaces with high and low cRGD (cyclic Arginine-Glycine-Aspartic acid) peptide ligand densities are used. The cRGD is diluted with a bioinert ligand to prevent surface native cellular remodeling. The cellular morphology, actin, and microtubules differ on these surfaces. Confocal fluorescence microscopes and atomic force microscopy (AFM) are used to determine the structural and mechanical cellular responses with and without microtubules. Microtubules are vital as an intracellular scaffold in elongated morphology correlated with low cRGD compared to rounded morphology in high cRGD substrates. The contributions of MTs to nucleus morphology and cellular mechanics are based on the underlying cRGD densities. Finally, this study reveals a significant correlation between MTs, actin networks, and vimentin in response to the underlying densities of cRGD.

Machine learning and artificial intelligence: Enabling the clinical translation of atomic force microscopy-based biomarkers for cancer diagnosis

The influence of biomechanics on cell function has become increasingly defined over recent years. Biomechanical changes are known to affect oncogenesis; however, these effects are not yet fully understood. Atomic force microscopy (AFM) is the gold standard method for measuring tissue mechanics on the micro- or nano-scale. Due to its complexity, however, AFM has yet to become integrated in routine clinical diagnosis. Artificial intelligence (AI) and machine learning (ML) have the potential to make AFM more accessible, principally through automation of analysis. In this review, AFM and its use for the assessment of cell and tissue mechanics in cancer is described. Research relating to the application of artificial intelligence and machine learning in the analysis of AFM topography and force spectroscopy of cancer tissue and cells are reviewed. The application of machine learning and artificial intelligence to AFM has the potential to enable the widespread use of nanoscale morphologic and biomechanical features as diagnostic and prognostic biomarkers in cancer treatment.

Compressive stresses in cancer: characterization and implications for tumour progression and treatment

Beyond their many well-established biological aberrations, solid tumours create an abnormal physical microenvironment that fuels cancer progression and confers treatment resistance. Mechanical forces impact tumours across a range of biological sizes and timescales, from rapid events at the molecular level involved in their sensing and transmission, to slower and larger-scale events, including clonal selection, epigenetic changes, cell invasion, metastasis and immune response. Owing to challenges with studying these dynamic stimuli in biological systems, the mechanistic understanding of the effects and pathways triggered by abnormally elevated mechanical forces remains elusive, despite clear correlations with cancer pathophysiology, aggressiveness and therapeutic resistance. In this Review, we examine the emerging and diverse roles of physical forces in solid tumours and provide a comprehensive framework for understanding solid stress mechanobiology. We first review the physiological importance of mechanical forces, especially compressive stresses, and discuss their defining characteristics, biological context and relative magnitudes. We then explain how abnormal compressive stresses emerge in tumours and describe the experimental challenges in investigating these mechanically induced processes. Finally, we discuss the clinical translation of mechanotherapeutics that alleviate solid stresses and their potential to synergize with chemotherapy, radiotherapy and immunotherapies.

Atomic force microscopy for characterization of decellularized extracellular matrix (dECM) based materials

In live organisms, cells are embedded in tissue-specific extracellular matrix (ECM), which provides chemical and mechanical signals important for cell differentiation, migration, and overall functionality. Careful reproduction of ECM properties in artificial cell scaffolds is necessary to get physiologically relevant results of in vitro studies and produce robust materials for cell and tissue engineering. Nanoarchitectonics is a contemporary way to building complex materials from nano-scale objects of artificial and biological origin. Decellularized ECM (dECM), remaining after cell elimination from organs, tissues and cell cultures is arguably the closest equivalent of native ECM achievable today. dECM-based materials can be used as templates or components for producing cell scaffolds using nanoarchitectonic approach. Irrespective of the form, in which dECM is used (whole acellular organ/tissue, bioink or hydrogel), the local stiffness of the dECM scaffold must be evaluated, since the fate of seeded cells depends on the mechanical properties of their environment. Careful dECM characterization is also necessary to reproduce essential ECM traits in artificial cell scaffolds by nanoparticle assembly. Atomic force microscopy (AFM) is a valuable characterization tool, as it allows simultaneous assessment of mechanical and topographic features of the scaffold, and additionally evaluate the efficiency of decellularization process and preservation of the extracellular matrix. This review depicts the current application of AFM in the field of dECM-based materials, including the basics of AFM technique and the use of flicker-noise spectroscopy (FNS) method for the quantification of the dECM micro- and nanostructure.

The Sentient Cell: Implications for Osteopathic Medicine

The Foundation of Osteopathic Research and Clinical Endorsement (FORCE) is an organization that includes various figures involved in clinical and non-profit research and does not depend on any private or government body. To better understand how the human body behaves, we need to observe cellular behavior. Considering the human body as layers, districts, and regions, or just as a machine, is severely limiting to understanding the systemic mechanisms that are implemented to maintain bodily health. For some years, FORCE has contributed several articles to the literature to support the view of a human body as a unit, a fascial continuum (solid and fluid fascia) capable of interacting consciously, and not as a passive mirror, with respect to external stresses. The article reviews the tensegrity theory applied to the cell, trying to bring to light that the mechanistic vision on which this theory is based does not meet biological reality. We review some concepts related to biology, the science that studies life, and quantum physics, the science that studies the invisible physical phenomena that underlie life. Understanding that the cells and tissues are aware of the therapeutic approaches they receive could better guide the decisions of the osteopathic clinician.