High subzero cryopreservation
This disclosure is related to methods of preserving biological samples, organs, and organisms. This disclosure is based, at least in part, on the discovery that in the presence of heterogenous extracellular ice, endothelial cells have improved attachment and viability after preservation, and particularly by uniformly nucleating ice across the microvasculature using ice nucleating agents, the chance of intracelluar ice formation can be significantly reduced.
1. A method for partially freezing a cell, the method comprising:
(a) incubating the cell in a loading solution comprising 3-O-methyl-D-glucopyranose (3-OMG) in a vessel, wherein a concentration of 3-OMG in the loading solution is from about 50 mM to about 200 mM, and wherein the cell is incubated at about 37° C. for about 2 hours;
(b) perfusing the vessel with a storage solution, wherein perfusing the vessel with the storage solution replaces the loading solution with the storage solution, wherein the storage solution comprises 3-OMG, one or more cryoprotective agents, and an ice nucleator, and wherein a concentration of 3-OMG in the storage solution is from about 50 mM to about 200 mM; and
(c) cooling the cell in the vessel to a temperature from −5° C. to −10° C., thereby partially freezing the storage solution in the vessel,
wherein from about 20% to about 99% of the storage solution in the vessel is in a solid state comprising extracellular ice crystals,
wherein the storage solution remains partially frozen during storage,
wherein the method avoids intracellular ice formation, and
wherein the method does not include vitrification.
2. The method of claim 1 , wherein the cell is a mammalian cell, and the method further comprises attaching the cell to the vessel.
3. The method of claim 2 , wherein the vessel is coated with fibronectin.
4. The method of claim 1 , wherein the vessel is a capillary tube.
5. The method of claim 1 , wherein the loading solution comprises EBM-2 complete media and 3-OMG.
6. The method of claim 1 , wherein the storage solution further comprises University of Wisconsin cold storage solution, wherein the University of Wisconsin cold storage solution comprises
about 100 mM potassium lactobionate,
about 25 mM KH2PO4,
about 5 mM MgSO4,
about 30 mM raffinose,
about 5 mM adenosine,
about 3 mM glutathione,
about 1 mM allopurinol, and
about 50 g/L hydroxyethyl starch.
7. The method of claim 1 , wherein the ice nucleator is InaZ of Pseudomonas syringae , and the one or more cryoprotective agents are selected from the group consisting of a sugar, glycerol, ethylene glycol, propylene glycol, polyethylene glycol (PEG), 1,2-propanediol, trehalose, and dimethyl sulfoxide (DMSO).
8. The method of claim 1 , wherein the storage solution further comprises trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), 3-O-methyl-D-glucopyranose, and polyethylene glycol (PEG).
9. The method of claim 8 , wherein the storage solution further comprises glycerol and trehalose.
10. The method of claim 1 , wherein the cell is partially frozen for more than 50 hours.
11. The method of claim 1 , wherein the cell is a human, porcine, murine, or bovine cell.
12. The method of claim 1 , wherein the cell is an oocyte, a sperm, a stem cell, an embryo, a zygote, or an endothelial cell.
13. The method of claim 1 , wherein the storage solution comprises about 25 mM trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), about 5% DMSO, and about 0.1 g/L InaZ of Pseudomonas syringae.