Method of cryopreserving cells

Abstract

A non-linear cooling cryopreservation method for improving cryopreservation protocols for cells that involves producing a simulation of cellular responses to a range of cooling parameters; determining optimal cooling parameters required to minimize cryoinjury to the cells using simulation of cellular responses and experimental results; and incorporating optimal parameters into the protocol. The simulation is based on mathematical models of cellular parameters. A non-linear cooling cryopreservation protocol for cryopreserving stem cells is also disclosed that does not require cryoprotectants.

Description

RELATED APPLICATIONS [0001] This application claims priority from U.S. Provisional Patent Application No. 60 / 611,391 entitled “Method of Cryopreserving Cells”, having a current filing date of Sep. 18, 2004, but for which a petition was filed to correct the filing date to Sep. 17, 2004; and to Canadian Patent Application Number 2,482,045, also entitled “Method of Cryopreserving Cells”, filed Sep. 17, 2004. All of such references are herein incorporated by reference.TECHNICAL FIELD [0002] This application relates to methods of cryopreservation, particularly methods of cryopreserving cells and tissues. BACKGROUND [0003] Cryobiology is the study of the effects of low temperatures on biological systems. Although freezing is lethal to most living systems, cryobiologists have been able to preserve cells and tissues at a range of subzero temperatures, as low as liquid nitrogen temperatures (−196° C.). Currently, cryoprotection can be applied to most cells in suspension, such as stem cells, ...

AI Technical Summary

Benefits of technology

[0009] This invention relates to any non-linear cooling cryopreservation method for cryopreserving cells and / or tissue that is comprised of determining an optimal cooling profile for maximum recovery of specific cells and tissues, and applying the cooling profile to the respective cells and tissues. By non-linear cooling cryopreservation method we mean throughout any cryopreservation protocol for which, by design, temperature versus time is other than a single straight line or a profile made of two line segments with different slopes. In one embodiment, a non-linear cooling cryopreservation method is achieved by a non-constant cooling rate during at least a portion of the method. In another embodiment the non-linear cryopreservation method is achieved by a two-step cooling process, wherein the cells or tissue are cooled at a constant or non-constant rate to a first holding temperature (referred to throughout as hold temperature) and then subsequently at a constant or non-constant rate to a second temperature (referred to throughout as storage temperature).

Problems solved by technology

Although the current recovery of viable cells post-thaw may be sufficient for some clinical uses, recovery is generally considered less than optimal due to injury during the freezing process.

High recovery is also important in cryopreservation of engineered cells due to the high cost and length of time for manufacturing such cells.

There are, however, limitations to the use of DMSO.

However, cooling profiles were not optimized and cell recoveries were not as high as with cryoprotectants.

To date an easy method that can optimize cooling profiles for a cell type or for various cell types for cryopreservation of cells is not available and a reliable method that does not use cryoprotectants, especially permeating cryoprotectants, has not been recommended, especially for clinical use of the cells.

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