Cell adhesion control using microstructured meshes induces self-assembly-mediated organoid formation by human iPS cells

The goal of this research was to investigate the effect of minimization of cell-substrate interaction on the differentiation specification of human pluripotent stem cells (hiPSCs). To achieve minimization of cell adhesion area, we designed and implemented a novel mesh culture method that involves culturing hiPSCs on thin mesh sheets consisting of relatively large mesh apertures (> 100 μm) and narrow mesh threads (<;5 μm in width) that are set suspended in the culture medium such that cell-substrate interaction can only occur along the fine mesh threads. We demonstrate that this mesh culture method can mechanically trigger the differentiation of hiPSCs into cells exhibiting trophoblast-like characteristics such as cyst formation, secretion of human chorionic gonadotropin (hCG) hormone and expression of trophoblast specific markers such as caudal type homeobox 2 (CDX2). This illustrates that modulating the passive mechanical factors emanating from cell-substrate interaction can determine lineage specification and even induce totipotency features in stem cells.