Cellular behavior regulation and adhesion force measurement based on flexible micropillar arrays

Systematic understanding of the interaction between cells and their microenvironment is of wide interest. To investigate this interaction, a flexible micropillar array device integrating dual functions of cell behavior regulation and adhesion measurement is developed. Micropillar arrays with high and low densities are designed to explore the role of substrate topography in the behavior of human bone marrow mesenchymal stem cells. In addition, a method is established for quantifying weak cell adhesion forces on the basis of micropillar deflections. The results show that cell cytoplasmic adhesion is greater on a low-density micropillar array than that on a high-density array and is localized mainly in the perinuclear region of the cytoplasm rather than in pseudopods. It is also found that the micropillar array topography facilitates the oriented spreading of cell morphology and pseudopod formation, and a reduction in focal adhesion aggregation and F-actin polarization compared with a flat substrate. Notably, cells cultured on a low-density micropillar array exhibited a higher number of pseudopods, stronger adhesion forces, and greater stiffness compared with those on a high-density array. In summary, this work employs an adhesion force sensor, immunofluorescence staining, and atomic force microscopy to investigate the mechanical properties of cells and elucidate the mechanisms by which micropillar topographical cues regulate the adhesion of mesenchymal stem cells to the substrate. The micropillar array force sensor developed in this study provides an effective tool for simultaneously modulating cell behavior and quantifying adhesion forces, offering valuable insights for biomechanical research.