Scientists at the Weizmann Institute of Science, Israel, have grown mouse embryos in bottles, offering a unique way to observe how a fetus develops.
The team took newly fertilised eggs from mice and placed them into gently spinning glass jars filled with a balance of nutrients and gases to keep the eggs alive – see also the Science article which includes a video.
Previous techniques could only sustain embryos for 3-4 days, but with this new technique embryos continued to grow successfully for 11 days - about halfway through mouse development.
At this stage, the embryos were identical to those growing in living mice, but were now too large to continue to grow without a blood supply.
The success will allow the researchers to study how limbs and organs develop in greater detail, and shed light on how problems arise during pregnancy.
“To us, that is the most mysterious and the most interesting part of embryonic development, and we can now observe it and experiment with it in amazing detail,” said group leader Professor Jacob Hanna.