Time-lapse mechanical imaging of neural tube closure in live embryo using Brillouin microscopy

ABSTRACT Neural tube closure (NTC) is a complex process of embryonic development involving molecular, cellular, and biomechanical mechanisms. While the genetic factors and biochemical signaling have been extensively investigated, the role of tissue biomechanics remains mostly unexplored due to the lack of tools. Here, we developed a new optical modality that can conduct time-lapse mechanical imaging of neural plate tissue as the embryo is experiencing neurulation. This technique is based on the combination of a confocal Brillouin microscope and an on-stage incubator for the modified ex ovo culturing of chick embryo. With this technique, for the first time, we captured the mechanical evolution of the neural plate tissue with live embryos. Specifically, we observed the continuous stiffening of the neural plate during NTC for ex ovo cultured embryos, which is consistent with the data of in ovo culture as well as previous studies. Beyond that, we found the tissue stiffening was highly correlated with the tissue thickening and bending. We foresee this non-contact and label-free technique can open new opportunities to understand the biomechanical mechanisms in development. Summary statement An all-optical technique is developed to capture the evolution of tissue mechanics during neural tube closure of live chick embryo.