Nature has been working for a decade to "synthesize" embryos with brains and beating hearts

The research team, led by Professor Magdalena Zernicka-Goetz, developed an embryonic model without eggs or sperm, but instead used stem cells – the body's master cells, which can develop into almost any type of cell

The researchers simulated natural processes in the lab, causing them to begin interacting

Stem cells self-organize to form structures that develop through successive stages of development until they have the basis of a beating heart and brain, as well as the yolk sac

The team says their findings could help researchers understand why some embryos fail while others continue to develop into healthy pregnancies

For a human embryo to develop successfully, there needs to be a "dialogue"

Zernica-Goetz, professor of mammalian developmental and stem cell biology in the Department of Humanities, Developmental and Neuroscience at Cambridge, said: "Our mouse embryonic model developed not only the brain, but also the beating heart, which are all the components

For the past decade, Professor Zernica-Goetz's team at the University of Cambridge has been studying the early stages of pregnancy to understand why some people fail to conceive and some succeed

Zernicka-Goetz said: "Stem cell embryo models are important because it allows us to understand the structure in development, and this stage is usually hidden from us because tiny embryos implant into the mother's

To guide the development of synthetic embryos, the researchers combined stem cells representing three tissues in the right proportions and environments to promote their growth and mutual communication, eventually assembling themselves into embryos

Zernicka-Goetz said: "This period of human life is so mysterious that being able to see how it happens in a dish — being able to access these individual stem cells, understanding why so many pregnancies fail, and how we might be able to prevent this from happening — is quite special

A major advance in this research is the ability to generate entire brains, especially the front part of the brain, which has been a major goal in the development of synthetic embryos

Zernicka-Goetz said: "This opens up new possibilities

While current research is being conducted on mouse models, researchers are developing similar human models that have the potential to directly produce specific organ types to understand the mechanisms behind key processes that would otherwise not have been studied in real embryos

If the methods developed by Zernica-Goetz's team prove successful on future human stem cells, they could also be used to guide the development of synthetic organs for patients

Gianluca Amadei, Charlotte E.