Composition for cryopreservation of cells and tissues
A composition for cryopreservation of cells and tissues of human and other animals in a safe manner without using toxic substances such as DMSO, as well as for freeze preserving or freeze-drying of foods and pharmaceuticals. In embodiments, ε-poly-L-lysine is reacted with succinic anhydride so that 60% or more of amino groups are blocked; and, thus obtained polymer compound is added to Dulbecco-modified eagle MEM culture medium (DMEM) on market sale to form a cryopreservation liquid. In embodiments for foods or pharmaceuticals, the ε-poly-L-lysine derivative was added by 0.5-10 wt % to curb freeze concentration.
1. A method for preserving cells or tissues, comprising: suspending or immersing the cells or tissues in a cryopreservative liquid; then, freezing the cryopreservative liquid, as well as the cells or tissues therein; and keeping them for a certain period and subsequently thawing them; wherein
said cryopreservative liquid is an aqueous solution comprising 1-50% by weight relative to the total weight of the cryopreservative liquid of a polyamine polymer compound comprised of a polymer of units having side-chain amino groups, said polymer of units being ε-poly-L-lysine; and
50-99 mol % of the amino groups, other than those forming amino-acid-to-amino-acid linkages, of said polymer compound are blocked with a carboxylic anhydride to form pendant moieties, each of which is linked to the main chain of the polymer via an amide linkage and has a free carboxylic acid group.
2. The method according to claim 1 , wherein said cryopreservative liquid is obtained by dissolving the polyamine polymer compound in a physiological solution.
3. The method according to claim 2 , wherein the physiological solution is saline, Dulbecco's Modified Eagle Medium (DMEM), or a culture medium for cells or tissues.
4. The method according to claim 1 , wherein said ε-poly-L-lysine has a number-average molecular weight in the range of 1000-20,000.
5. The method according to claim 1 , wherein remaining side-chain amino groups or remaining side-chain and terminal amino groups of the at least one polymer compound are not blocked by covalent bonding.