Integrating nanoscale technologies with cryogenics: a step towards improved biopreservation.

At the beginning of the 20th century, successful preservation methods for cells and tissues were developed with new insights into biology and physics. In nature, we have already seen interesting examples of biopreservation. For instance, species such as water-bears (e.g., Tardigrada) and distinct frog types (e.g., Rana sylvatica) can survive in extremely cold temperatures by replacing the water in their bodies with highly concentrated glucose, which serves as an antifreezing agent [1]. These species can keep their metabolism at minimal levels under belowfreezing conditions. Inspired by nature, the holy grail of cryopreservation is to stop or slow down cellular and biological activity by bringing cells down to low temperatures, and later, to be able to restore function at physiological temperatures [2]. The major interest in biopreservation is driven by advances in medicine and biology, along with emerging clinical needs. Various cell types, including stem cells, embryonic cells, genetically modified cells, cancer cells, hematopoietic cells, germ cells and adult stromal cells are routinely cryopreserved for both research and clinical purposes. The scope of cryopreservation covers preservation of fertility, cell therapies, reproductive medicine, regenerative medicine, stem cell research, blood preservation and handling of organs prior to transplantation. In addition to these applications, long-term preservation of animal and plant cells as well as the genetic material of endangered species are also in the scope of cryopreservation. Although there has been significant progress in biopreserving various cell types, the existing procedures cause cryo-injury, such as dehydration of cells, loss of cell membrane integrity, alterations in functionality by potential