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 foods or pharmaceuticals,
comprising: suspending or immersing foods or pharmaceuticals in a cryopreservative liquid; and then, freezing the cryopreservative liquid as well as the foods or pharmaceuticals; wherein
said cryopreservative liquid is an aqueous solution comprising 1-15% by weight relative to the total weight of the cryopreservative liquid of one or more polyamine polymer compounds comprising one or more polymers of units having side-chain amino groups, said polymers of units being ε-poly-L-lysine; and wherein
48-80 mol % of the amino groups, other than those forming amino-acid-to-amino-acid linkages, of said polymer compounds are blocked with a carboxylic anhydride to form pendant moieties, each of which is linked to the main chain of the polymer of units via an amide linkage and has a free carboxylic acid group.
2. The method according to claim 1 , further comprising freeze-drying of the cryopreservative liquid as well as the foods or pharmaceuticals.
3. The method according to claim 1 , wherein said polymer compound is ε-poly-L-lysine having number-average molecular weight in the range of 1000-20,000.
4. The method according to claim 1 , wherein remaining side-chain amino groups or remaining side-chain and terminal amino groups of the polymer compound are not blocked by covalent bonding.