GLASS STABILITY AND ANNEALING BEHAVIOUR IN PLANT VITRIFICATION SOLUTIONS NO. 1 AND NO. 3.

ALINE SCHNEIDER TEIXEIRA; MILOS FALTUS; JIRÝ ZÁMECNÝK; ANTONIO D. MOLINA-GARCÍA

CRYO-LETTERS

CRYO LETTERS

Lugar: Londres; Año: 2019 vol. 40

0143-2044

Cryopreservation of biological specimens is currently performed for wide varieties of organisms, cells and tissues. Their viability and biological characteristics maintenance over long storage periods at low temperatures relies on the vitrification of their cellular content. Avoidance of ice formation both during cooling and warming has taken most of the researchers? work and effort, as the achievement of ice-free vitrification was considered guarantee of indefinite avoidance of deleterious changes. However, recent findings focused on certain systems and extended storage periods, shed doubts on this paradigm. Some specimens lose viability under conditions not directly explained by ice formation or previous treatments. The evolution of vitrified specimens is suspected to cause this loss of viability. Although glassy water is still considered unable to produce the feared and lethal ice crystals, and the extremely high viscosity precludes large-scale changes, other residual movements could be determinant of the observed changes. Glassy state stability has also attracted workers? attention, suspecting that the relaxation phenomena underwent by some glasses might affect cells and their components, such as biological membranes or nucleic acids. The relaxation behavior of relatively complex systems such as vitrification solutions (not to speak of real cellular content) is not completely known. To understand the fate of these solutions below glass transition (TG), a storage and annealing study was performed employing the well-known plant cryopreservation solutions No.1 (PVS1) and No.3 (PVS3), chosen for their clearly different vitrification behavior. Storage under their corresponding TG showed no significant effect on their vitrification parameters, even for as long as 60 days. However, an annealing protocol in which solutions were cycled between temperatures over and under TG, resulted in the apparition of annealing areas whose evolution with the target temperature employed in cycles could be studied. PVS3 glass was concluded to present further stability than PVS1 glass.