The concept of cooling organic materials in order to slow their decay is as old as civilization itself. For the preservation of food, it is as simple as freezing with ice to prevent bacterial or fungal growth; at worst, what occurs at both the tissue and cellular levels results in texture and consistency changes, altering the taste of what was frozen but not impacting its safety.
Yet what occurs at the cellular level to cause this shift is ultimately highly destructive – the formation of ice crystals which can rupture and tear cells apart. This ice damage, while less concerning in food, is catastrophic for cell therapies. This requires freezing solutions to prevent ice formation, allowing for the retention of cells’ therapeutic functionality. For these modalities, as well as any tissue preserved for medical use, the need to preserve them in ways which allow them to revert to healthy cells after preservation has created complexity for the drug developers pursuing these therapies to treat rare and often intractable diseases.