Tracking intracellular forces and mechanical property changes in mouse one-cell embryo development

We identify a program of forces and changes to the cytoplasmic mechanical properties required for mouse embryo development from fertilization to the first cell division. Injected, fully internalized chips responded to sperm decondensation and recondensation, and subsequent device behavior suggested a model for pronuclear convergence based on a gradient of effective cytoplasmic stiffness. The nanodevices reported reduced cytoplasmic mechanical activity during chromosome alignment and indicated that cytoplasmic stiffening occurred during embryo elongation, followed by rapid cytoplasmic softening during cell division. Forces greater than those inside muscle cells were detected. These results suggest that intracellular forces are part of a concerted program that is necessary for development at the origin of a new embryonic life.
Nat. Mater. (2020)