Video provides an up-close look at a human embryo plunging into tissue that simulates the uterine lining.
By Jenna Ahart, 15 August 2025
A time-lapse film offers a glimpse of a hidden milestone of human development: the moment when the newly formed embryo latches onto the uterine lining. Researchers have captured real-time footage of an embryo pulling on a high-fidelity replica of the lining to bury itself inside, effectively remodelling its new home.
The team reports its findings today in Science Advances1.
Hidden figures
The authors were inspired to simulate the implantation process because the actual events are so difficult to capture. “It’s very inaccessible because it’s all happening inside the mother,” says co-author Samuel Ojosnegros, a bioengineer at the Institute for Bioengineering of Catalonia (IBEC) in Barcelona, Spain. “It’s such an important process for human reproduction, but at the same time, we don’t have the technology to study it.”
Although previous studies have investigated how human embryos interact with glass, the embryo can’t penetrate this material as it does real human tissue. So the team set out to create a more lifelike mock-up, devising a faux uterine lining from a gel rich in collagen and proteins that are crucial for embryonic development.
To shoot their stop-motion film, researchers placed human embryos donated by a local hospital near the gel. As the embryo attached to the ‘uterus’, the team used a microscope to capture an image about every 20 minutes for 16–24 hours, and then stitched the stills together.
Co-author Amélie Godeau, a biomechanics researcher at IBEC, was shocked to see how quickly the embryo burrowed down into the gel. “My first reflex was to think my experiment had gone wrong and there was some drift in the microscope,” Godeau says. By contrast, the team found that mouse embryos adhere to the surface of the uterus rather than embedding themselves inside.
It was known that the human embryo releases enzymes to break down the uterine lining during implantation. But the new study also suggests that the embryo must exert some sort of extra force on the uterus to lodge itself there, pulling at the intricate network of tissue so it can cosy up inside.
Ripla Arora, a uterine biologist at Michigan State University in East Lansing, says this study is the first to document the mechanics of the implantation process in such detail — although she’d be interested to see how the uterus might reciprocate by applying force back on the embryo. “An exciting next step is to know what the uterus is doing in this scenario, but that’s harder to mimic,” Arora says.
In the future, Godeau would like to study why some healthy embryos fail to attach to the uterus, or to follow the process of implantation over a longer period. “Just by looking one day later at the distribution of forces, we may learn even more about how this implantation is happening,” she says.
doi: https://doi.org/10.1038/d41586-025-02627-2
References
Godeau, A. L. et al. Sci. Adv. 11, eadr5199 (2025).
(Sources: Nature)
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