Huang, Q. et al. Science 368, 181–186 (2020)

Direct, real-time observations of whole mouse embryos have long been obscured by the dam’s body. To overcome this limitation, researchers at Duke University and MIT recently developed a new approach that provides a window–literally–into intrauterine development.

The team designed a small, 10 mm wide and 1.5 mm deep window with glass coverslip that can be surgically implanted into the mother’s uterus at embryonic day 9.5, without lasting negative effects on the developing pups. The embryos can be visualized at cellular resolution, and, with coverslip removed, manipulated. In their paper, the researchers used the window to observe several fluorescently labelled neurons over time, deliver genes via adeno-associated virus vectors, perform in utero electroporation, and produce blastocyst chimeras.