Polymeric Sheet Actuators with Programmable Bioinstructivity

Raw data from the figures in the paper published in Proceedings of the National Academy of Sciences - Polymeric Sheet Actuators with Programmable Bioinstructivity (add proper reference once we have it)

Stem cells are capable of sensing and processing environmental inputs, converting this information to output a specific cell lineage through signaling cascades. Despite the combinatorial nature of mechanical, thermal and biochemical signals, these stimuli have typically been decoupled and applied independently, requiring continuous regulation by controlling units. We employ a programmable polymer actuator sheet to autonomously synchronize thermal and mechanical signals applied to mesenchymal stem cells (MSCs). Using a grid on its underside, the shape change of polymer sheet, as well as cell morphology, calcium (Ca²⁺) influx and focal adhesion assembly, could be visualized and quantified. This paper gives compelling evidence that the temperature sensing and mechanosensing of MSCs are interconnected via intracellular Ca²⁺. Upregulated Ca²⁺ levels lead to a remarkable alteration of histone H3K9 acetylation and activation of osteogenic related genes. The interplay of physical, thermal and biochemical signaling was utilized to accelerate the cells’ differentiation towards osteogenic lineage. The approach of programmable bioinstructivity provides a fundamental principle for functional biomaterials exhibiting multifaceted stimuli on differentiation programs. Technological impact is expected in the tissue engineering of periosteum for treating bone defects.