METHOD AND SYSTEM FOR NUCLEATION CONTROL IN CRYOPRESERVATION OF BIOLOGICAL MATERIALS

摘要

A method and system for controlled rate freezing and nucleation of materials is provided. The presently disclosed system and method provides the ability to rapidly cool the materials contained in vials or other containers within a cooling unit via forced convective cooling using a laminar and uniform flow of cryogen in proximity to the plurality of vials disposed within the cooling unit. The rapid cooling of the biological materials is achieved by precisely controlling and adjusting the temperature of the cryogen being introduced to the system as a function of time. Nucleation may be induced using either temperature quench or pressure induced nucleation control methods. When using a temperature quench to control nucleation, the temperature profile versus time of the cryogenic gas comprises a temperature quench step (408), during which the temperature of the cryogenic cold gas is adjusted to a temperature sufficiently low to ensure nucleation of the material in each vial or container. After nucleating the material an optional temperature quench hold step (410) may be applied. Alternatively, a pressure applied to the material in each of the plurality of containers is decreased to initiate and control nucleation.