Scientists have created “artificial embryos” using stem cells from mice, in what they believe is a world first.
The University of Cambridge team used two types of stem cells and a 3D scaffold to create a structure closely resembling a natural mouse embryo.
Previous attempts have had limited success because early embryo development requires the different cells to coordinate with each other.
The researchers hope their work will help improve fertility treatments.
It could also provide useful insights into the way early embryos develop.
However, experimentation on human embryos is strictly regulated, and banned after 14 days.
Once a mammalian egg has been fertilised, it divides to generate embryonic stem cells - the body’s “master cells”.
These embryonic stem cells cluster together inside the embryo towards one end, forming the rudimentary embryonic structure known as a blastocyst.
The Cambridge team, whose work is published in the journal Science, created their artificial embryo using embryonic stem cells and a second type of stem cell - extra-embryonic trophoblast stem cells - which form the placenta.
Lead researcher Prof Magdalena Zenricka Goetz said: “We knew that interactions between the different types of stem cell are important for development, but the striking thing that our new work illustrates is that this is a real partnership - these cells truly guide each other.”
However, the researchers say their artificial embryo is unlikely to develop into a healthy foetus as it would probably need the third form of stem cell, which develops into the yolk sac that provides nutrition.