Artificial embryo grown in a dish from two types of stem cells

Artificial mouse embryos grown from stem cells in a dish could help unlock secrets of early development and infertility that have until now evaded us. 

Magdalena Zernicka-Goetz at the University of Cambridge and her team made the embryos using embryonic stem cells, the type of cells found in embryos that can mature into any type of tissue in the body.

The trick was to grow these alongside trophoblast stem cells, which normally produce the placenta. By growing these two types of cell separately and then combining them in a special gel matrix, the two mixed and started to develop together.

After around four-and-a-half days, the embryos resembled normal mouse embryos that were about to start differentiating into different body tissues and organs.

“They are very similar to natural mouse embryos,” says Zernicka-Goetz. “We put the two types of stem cells together – which has never been done before – to allow them to speak to each other. We saw that the cells could self-organise themselves without our help.”

This is the first time something resembling an embryo has been made from stem cells, without using an egg in some way. Techniques such as cloning, as done for Dolly the sheep and other animals, bypass the need for sperm, but still require an egg cell.

The artificial embryos are providing new insights into how embryos organise themselves and grow, says Zernicka-Goetz. The team engineered the artificial embryos so the cell types fluoresced in different colours, to reveal their movements and behaviour as the embryos go through crucial changes.