Patent ID: 6982172

Claim:
A method for cryopreservation of bovine oocyte morphology and viability, comprising the steps: (a) suspending bovine oocytes in a medium comprising about 4% ethylene glycol and about 20% bovine serum for about 15 min at a temperature at or near physiological temperatures; (b) rinsing the oocytes for about 30 seconds in a solution comprising about 35% ethylene glycol, 0.4 M trehalose, 20% bovine serum and 5% polyvinylpyrrolidone; (c) vitrifying the oocytes in step (b) by quickly dropping microdroplets of the solution comprising the oocytes onto a solid surface that has a temperature between −150° C. and −180° C.; and (d) collecting frozen microdroplets that contain vitrified oocytes that maintain morphology and viability after thawing.