Atomic force microscopy reveals the mechanical properties of breast cancer bone metastases

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.

The application of nanomaterials in tumor therapy based on the regulation of mechanical properties

Mechanical properties, as crucial physical properties, have a significant impact on the occurrence, development, and metastasis of tumors. Regulating the mechanical properties of tumors to enhance their sensitivity to radiotherapy and chemotherapy has become an important strategy in the field of cancer treatment. Over the past few decades, nanomaterials have made remarkable progress in cancer therapy, either based on their intrinsic properties or as drug delivery carriers. However, the investigation of nanomaterials of mechanical regulation in tumor therapy is currently in its initial stages. The mechanical properties of nanomaterials themselves, drug carrier targeting, and regulation of the mechanical environment of tumor tissue have far-reaching effects on the efficient uptake of drugs and clinical tumor treatment. Therefore, this review aims to comprehensively summarize the applications and research progress of nanomaterials in tumor therapy based on the regulation of mechanical properties, in order to provide strong support for further research and the development of treatment strategies in this field.

Biomechanical Aspects in Bone Tumor Engineering

In the past decades, anticancer drug development brought the field of tumor engineering to a new level by the need of robust test systems. Simulating tumor microenvironment in vitro remains a challenge, and osteosarcoma-the most common primary bone cancer-is no exception. The growing evidence points to the inevitable connection between biomechanical stimuli and tumor chemosensitivity and aggressiveness, thus making this component of the microenvironment a mandatory requirement to the developed models. In this review, we addressed the question: is the "in vivo - in vitro" gap in osteosarcoma engineering bridged from the perspective of biomechanical stimuli? The most notable biomechanical cues in the tumor cell microenvironment are observed and compared in the contexts of in vivo conditions and engineered three-dimensional in vitro models. Impact statement The importance of biomechanical stimuli in three-dimensional in vitro models for drug testing is becoming more pronounced nowadays. This review might assist in understanding the key players of the biophysical environment of primary bone cancer and the current state of bone tumor engineering from this perspective.

Atomic force microscopy in disease-related studies: Exploring tissue and cell mechanics

Despite significant progress in human medicine, certain diseases remain challenging to promptly diagnose and treat. Hence, the imperative lies in the development of more exhaustive criteria and tools. Tissue and cellular mechanics exhibit distinctive traits in both normal and pathological states, suggesting that "force" represents a promising and distinctive target for disease diagnosis and treatment. Atomic force microscopy (AFM) holds great promise as a prospective clinical medical device due to its capability to concurrently assess surface morphology and mechanical characteristics of biological specimens within a physiological setting. This review presents a comprehensive examination of the operational principles of AFM and diverse mechanical models, focusing on its applications in investigating tissue and cellular mechanics associated with prevalent diseases. The findings from these studies lay a solid groundwork for potential clinical implementations of AFM. RESEARCH HIGHLIGHTS: By examining the surface morphology and assessing tissue and cellular mechanics of biological specimens in a physiological setting, AFM shows promise as a clinical device to diagnose and treat challenging diseases.

Recent progress of mechanosensitive mechanism on breast cancer

The mechanical environment is important for tumorigenesis and progression. Tumor cells can sense mechanical signals by mechanosensitive receptors, and these mechanical signals can be converted to biochemical signals to regulate cell behaviors, such as cell differentiation, proliferation, migration, apoptosis, and drug resistance. Here, we summarized the effects of the mechanical microenvironment on breast cancer cell activity, and mechanotransduction mechanism from cellular microenvironment to cell membrane, and finally to the nucleus, and also relative mechanosensitive proteins, ion channels, and signaling pathways were elaborated, therefore the mechanical signal could be transduced to biochemical or molecular signal. Meanwhile, the mechanical models commonly used for biomechanics study in vitro and some quantitative descriptions were listed. It provided an essential theoretical basis for the occurrence and development of mechanosensitive breast cancer, and also some potential drug targets were proposed to treat such disease.

Atomic Force Microscopy Methods to Measure Tumor Mechanical Properties

Atomic force microscopy (AFM) is a popular tool for evaluating the mechanical properties of biological materials (cells and tissues) at high resolution. This technique has become particularly attractive to cancer researchers seeking to bridge the gap between mechanobiology and cancer initiation, progression, and treatment resistance. The majority of AFM studies thus far have been extensively focused on the nanomechanical characterization of cells. However, these approaches fail to capture the complex and heterogeneous nature of a tumor and its host organ. Over the past decade, efforts have been made to characterize the mechanical properties of tumors and tumor-bearing tissues using AFM. This has led to novel insights regarding cancer mechanopathology at the tissue scale. In this Review, we first explain the principles of AFM nanoindentation for the general study of tissue mechanics. We next discuss key considerations when using this technique and preparing tissue samples for analysis. We then examine AFM application in characterizing the mechanical properties of cancer tissues. Finally, we provide an outlook on AFM in the field of cancer mechanobiology and its application in the clinic.

Hyperelastic characterization reveals proteoglycans drive the nanoscale strain-stiffening response in hyaline cartilage

Degenerative diseases such as osteoarthritis (OA) result in deterioration of cartilage extracellular matrix (ECM) components, significantly compromising tissue function. For measurement of mechanical properties at micron resolution, atomic force microscopy (AFM) is a leading technique in biomaterials research, including in the study of OA. It is common practice to determine material properties by applying classical Hertzian contact theory to AFM data. However, errors are consequential because the application of a linear elastic contact model to tissue ignores the fact that soft materials exhibit nonlinear properties even at small strains, influencing the biological conclusions of clinically-relevant studies. Additionally, nonlinear material properties are not well characterized, limiting physiological relevance of Young's modulus. Here, we probe the ECM of hyaline cartilage with AFM and explore the application of Hertzian theory in comparison to five hyperelastic models: NeoHookean, Mooney-Rivlin, Arruda-Boyce, Fung, and Ogden. The Fung and Ogden models achieved the best fits of the data, but the Fung model demonstrated robust sensitivity during model validation, demonstrating its ideal application to cartilage ECM and potentially other connective tissues. To develop a biological understanding of the Fung nonlinear parameter, we selectively degraded ECM components to target collagens (purified collagenase), hyaluronan (bacterial hyaluronidase), and glycosaminoglycans (chondroitinase ABC). We found significant differences in both Fung parameters in response to enzymatic treatment, indicating that proteoglycans drive the nonlinear response of cartilage ECM, and validating biological relevance of these phenomenological parameters. Our findings add value to the biomechanics community of using two-parameter material models for microindentation of soft biomaterials.

Mesoscience in cell biology and cancer research

Mesoscale characteristics and their interdimensional correlation are the focus of contemporary interdisciplinary research. Mesoscience is a discipline that has the potential to radically update the existing knowledge structure, which differs from the conventional unit-scale and system-scale research models, revealing a previously untouchable area for scientific research. Integrative biology research aims to dissect the complex problems of life systems by conducting comprehensive research and integrating various disciplines from all biological levels of the living organism. However, the mesoscientific issues between different research units are neglected and challenging. Mesoscale research in biology requires the integration of research theories and methods from other disciplines (mathematics, physics, engineering, and even visual imaging) to investigate theoretical and frontier questions of biological processes through experiments, computations, and modeling. We reviewed  integrative paradigms and methods for the biological mesoscale problems (focusing on oncology research) and prospected the potential of their multiple dimensions and upcoming challenges. We expect to establish an interactive and collaborative theoretical platform for further expanding the depth and width of our understanding on the nature of biology.

Supramolecular Combination Chemotherapy: Cucurbit[8]uril Complex Enhanced Platinum Drug Infiltration and Modified Nanomechanical Property of Colorectal Cancer Cells

Combination chemotherapy is recognized as a vital medical treatment for cancer, but it has not achieved clinical ideal effects of combination therapy. Herein, we designed a supramolecular combination chemotherapy strategy based on cucurbit[8]uril (CB[8]), which can be facilely assembled into dual platinum drugs. Interestingly, employing the CB[8] carrier led to a greater than 10-fold intracellular Pt content compared to that of dual drugs at 4 h, and the CB[8] complex (CLE) can enhance the infiltration of platinum drugs in colorectal tumor cells tremendously. The platinum drugs can be released from CLE through consuming more tumor biomarker spermidine. Through analyzing the nanomechanical property of the colorectal tumor cellular surface by bioscope AFM, it was revealed that CLE modified the property by decreasing the adhesion and increasing the stiffness. This study provided a facile and sensitive strategy for improving combination chemotherapy by supramolecular materials.