Insights from Nanoscale Mass Measurements and Mechanical Properties

By guest author Angelo Gaitas.

Irene C. Turnbull^1,2,*, Angelo Gaitas³

¹Cardiovascular Research Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.

²The Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
³BioMedical Engineering & Imaging Institute, Leon and Norma Hess Center for Science and Medicine, New York, NY 10029, USA

Link to publication: Characterizing Induced Pluripotent Stem Cells and Derived Cardiomyocytes: Insights from Nanoscale Mass Measurements and Mechanical Properties

#Done with a FLEX: The most flexible atomic force microscope for materials research

In our recent paper, we leveraged atomic force microscopy (AFM) (FlexAFM (Nanosurf AG, Switzerland)) and FluidFM (Cytosurg AG, Switzerland) to delve into the nanoscale properties of human induced pluripotent stem cells (iPSCs) and their derivatives, cardiomyocytes (iPSC-CMs). Our investigation centered on the nano-mechanical aspects of elasticity and cell mass, which undergo significant changes as iPSCs differentiate into cardiomyocytes. These findings are pivotal, offering a novel method for evaluating the differentiation process of iPSCs into iPSC-CMs, a key area of interest due to their promising applications in cell therapy, drug testing, and understanding cardiac diseases. The differentiation of iPSCs into cardiomyocytes is a complex process, critical for advancing regenerative medicine and personalized medicine approaches. iPSC-CMs, derived from reprogrammed mature cells such as skin cells, hold the potential for heart tissue repair and the development of subject-specific drug testing models. This underscores the importance of precise single-cell level characterization for enhancing the understanding and application of these cells in medical science.

Our research employed two specific AFM techniques to accurately measure the elasticity and mass of individual iPSCs and iPSC-CMs. These measurements are crucial as they reflect the cellular health, growth rate, and the cell's functional state, providing insights into cellular behavior and the differentiation process. For instance, elasticity or stiffness of a cell is intrinsically linked to its cytoskeletal organization, which changes significantly during differentiation, influencing cell functionality and its state of maturation. By using AFM for these measurements, we not only confirmed the significant differences in cell mass and elasticity between undifferentiated iPSCs and differentiated iPSC-CMs but also demonstrated the potential of AFM as a comprehensive tool for single-cell analysis. This marks the first instance where such differences were quantitatively reported, highlighting the effectiveness of AFM in distinguishing between cells pre- and post-differentiation. Furthermore, our study presents the promising integration of fluidic-AFM techniques for mass measurement, opening new avenues for non-invasive cellular analysis. This could potentially be combined with other techniques for extracting genomic content from individual cells, thereby enriching our understanding of iPSC differentiation processes at a granular level.

In conclusion, our research underscores the critical role of nano-mechanical measurements in monitoring iPSC differentiation into cardiomyocytes. The differences in cell mass and elasticity we identified serve as important morphological markers for this process. While our findings are specific to the tested iPSC cell line, they suggest a broader applicability of AFM in cell biology, promising for future studies across various cell types and lines. This work paves the way for more detailed and integrative approaches to studying cell differentiation, enhancing the potential of iPSCs in regenerative medicine and beyond.

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Determining mass of individual micron-sized particles using PicoBalance and FluidFM® probes