Reducing Intracellular Ice Formation in Advanced Cell Models

Researchers at the University of Warwick have discovered a way for storing advanced cell models.

Confocal microscopy images showing live/dead staining of 3D cell constructs. The top row shows a fresh spheroid. The middle row shows the outcome of conventional cryopreservation and the bottom row the outcome of the new approach, which yields a much greater fraction of live cells post-thaw. Image Credit: University of Warwick.

The technology, which was published in the journal JACS Au, has the potential to improve the cryopreservation of cells, tissue culture, and 3D cell models for usage in a number of applications such as research, medical therapies, and agriculture.

Cryopreservation is the freezing of cells at extremely low temperatures in order to preserve them for eventual use. When cells are frozen, however, ice can develop inside the cells, causing harm or death. This is especially problematic for 2D and 3D cellular models, which mimic some of the features of organs and have complicated structures that make cryoprotectants difficult to reach all of their constituent cells.

To ensure that ice develops outside of cells, the scientists at the University of Warwick used soluble ice nucleating polysaccharides (a type of molecule that reacts with ice) produced by tree pollens. This aids in the prevention of harmful ice buildup in cell interiors. The approach was evaluated on a number of 2D and 3D tissue models and shown to be successful in decreasing intracellular ice formation and increasing cell viability.

The breakthrough is especially important because the US Food and Drug Administration has removed the necessity for new drugs to be tested on animals, raising the need for ways for preserving and transporting organ-like cell models.

Cryopreservation is essential across all biomedical research and drug discovery. Most people assume cryopreservation is focused on stopping ice forming, but it is actually essential to help ice form, at the highest temperature possible. We achieved this, and show that by helping the ice form we can dramatically improve the recovery of these cells.”

Dr Thomas Whale, Department of Chemistry, University of Warwick

“This innovative work has been inspired by nature, which has evolved elegant solutions to control exactly when, and where ice forms. Our discovery shows that we can store complex cell models in a freezer, so they are ‘ready to use’, to advance basic biomedical research. Another advance is that wider available of complex cell models may reduce the need for animal testing in the drug development process,” says Professor Matthew Gibson, Department of Chemistry, University of Warwick.