Researchers have developed a way to put stem cells and embryos to sleep for up to two weeks, then recover them to continue their development. The medium is a worm gel created in 2012 by Steven Ames and his colleagues at the University of Sheffield.

The discovery allows scientists to preserve the cells with virtually no maintenance, whereas before this development cells had to be constantly proliferated to be pluripotent, or frozen in liquid nitrogen, which allowed for potential damage.

Hydrogel induces suspended animation for stem cells. Placing the cells in a hydrogel storage medium keeps them dormant, where they can be reawakened for additional research and development. The gel has thin, long, worm-like micelles of a PGMA-PHPMA diblock copolymer. Spheres are created from the worms when the gel is cooled, breaking the gel down. When heated, the worms reform, fusing together end to end. The researchers found that the stem cells stored in the worm gel did not multiply, and the cells entered an arrested development phase, verified by the presence of a particular nuclear envelope protein, statin, that is associated with cell stasis.

The gel works as well with embryos, placing them into a stasis period known as diapause, for up to two weeks. The gel allows them to halt the growth phase of the embryos while also protecting them.

The research has the potential to allow the transport of stem cells with little or no damage, while providing a way to study the factors that influence cell behavior at different stages of development.