Characteristics of human induced pluripotent stem cells cultured on soft substrates.

This study investigated the impact of culture surface rigidity on the proliferation and maintenance of undifferentiated human induced pluripotent stem cells (hiPSCs), which are crucial in regenerative medicine and stem cell-based organ therapy. Given the need for a substantial number of cells per patient, there is a pressing demand for methods that ensure homogeneous and efficient large-scale cultivation of hiPSCs. Mechanotransduction, the process by which cells, including hiPSCs, respond to mechanical stimuli, has gained significant attention. We evaluated the effects of varying culture surface rigidity, examining changes in morphology, gene expression, and differentiation tendencies. Soft gels were made by altering acrylamide gel polymerization on functionalized glass slides, which were then coated with laminin. Cell attachment rates were quantified 24 h after seeding which varied according to substrate rigidity. The apparent proliferation rate was highest at 5 kPa, suggesting that hiPSCs sense rigidity. We further confirmed that this mechanosensing occurred through activation of the Hippo signaling pathway. In conclusion, this study revealed that the adhesion and proliferation of hiPSCs are significantly influenced by culture surface rigidity, with 5 kPa identified as the optimal condition for proliferation. This understanding may help optimize cell culture conditions for future organ regeneration and therapeutic applications. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10616-026-00895-y.