Long-term preservation of viable and functional biological systems

The long-term preservation of biological systems represents a major challenge in a wide range of industrial and academic fields, including research, healthcare, biotechnology and the food industry. Research carried out over the last few decades has enabled us to understand the main principles involved in the reversible and controlled suspension of cellular or tissue activity. The number of applications continues to grow, and it is now possible to preserve microbial cells (ferments, probiotics, collection strains, etc.), plant and animal cells and tissues (blood cells, stem cells, tissues, embryos, organs) for varying lengths of time. However, effective long-term organ and tissue preservation is still rare.

Preservation methods for biological systems are based on two processes: dehydration and freezing. Both of these methods lead to a sharp increase in intracellular viscosity, thus greatly slowing down cellular degradation reactions. However, the use of these methods can lead to cellular alterations that can result in cell death. Controlling the operational parameters of dehydration and freezing processes, which determine heat and mass transfer, is a key factor in optimizing the survival of the biological systems to be preserved.

The aim of this chapter is threefold:

• describe the state of knowledge acquired ;

  take stock of successful applications and technologies developed ;

  outline the prospects for this booming technological and scientific field.