Automated System for Cryopreservation of Oocytes, Embryos, or Blastocysts

Abstract

An automated system and method of cryopreservation of oocytes, embryos, or blastocysts. The method entails delivering two or more solutions into a container holding oocytes, embryos, or blastocysts, and controlling the flow of the solutions to gradually change the concentration of cryoprotectants and dehydrating agents in the container to minimize shock to the oocytes, embryos or blastocysts.

We claim: 
     
         1 . A system for preparing oocytes, embryos or blastocysts for cryopreservation, said system comprising:
 a container configured to hold one or more oocytes, embryos or blastocysts therein, and an inlet conduit and an outlet conduit, with an outlet valve controlling flow through the outlet conduit;   a first reservoir containing a first solution comprising a first stabilizing agent, and a first conduit connecting the first reservoir to the container, with a first valve controlling flow through the first conduit;   a second reservoir containing a second solution comprising a second stabilizing agent and a cryoprotectant, and a second conduit connecting the second reservoir to the container, with a second valve controlling flow through the second conduit;   a third reservoir containing a third solution comprising a cryoprotectant and a dehydrating agent, and a third conduit connecting the third reservoir to the container, with a third valve controlling flow through the third conduit; and   a controller operably connected to the first, second and third valves, said controller programmed to operate the first, second and third valves to:   operate the first valve to deliver the first solution into the container for a first time period;   while a portion of the first solution remains in the container, operate the second valve to deliver the second solution into the container, to gradually increase the concentration of cryoprotectant in the container;   while a portion of the second solution remains in the container, operate the third valve to deliver the third solution into the container, to gradually increase the concentration of dehydrating agent in the container.   
     
     
         2 . The system of  claim 1 , further comprising:
 a fourth reservoir containing a fourth solution comprising a cryoprotectant and a dehydrating agent, and a fourth conduit connecting the fourth reservoir to the container, with a fourth valve controlling flow through the fourth conduit;   wherein the controller is further programmed to:   while a portion of the third solution remains in the container, operate the fourth valve to deliver the fourth solution into the container, to gradually increase the concentration of dehydrating agent in the container.   
     
     
         3 . The system of  claim 1 , wherein the container comprises a track, the track including:
 a hollow tube forming a substantially circular loop, the hollow tube configured for conveying the one or more oocytes, embryos or blastocysts within;   a first port disposed on the hollow tube, the first port adapted for insertion into and extraction from the hollow tube of the one or more oocytes, embryos or blastocysts;   a second port disposed on the hollow tube, the second port in fluid communication with the inlet conduit; and   at least one opening disposed on the hollow tube for discharge of the fluid from the hollow tube, the at least one opening configured to prohibit discharge of the one or more oocytes, embryos or blastocysts.   
     
     
         4 . The system of  claim 1 , wherein the controller is further programmed to operate the second or third valves to deliver the second and/or third solutions to gradually increase the concentration of cryoprotectant in the container from about 0.0 M to about 1.5 M. 
     
     
         5 . The system of  claim 1 , wherein the controller is further programmed to operate the third valve to deliver the third solution to gradually increase the concentration of dehydrating agent in the container from about 0.0 M to about 0.3 M. 
     
     
         6 . The system of  claim 1 , wherein the first stabilizing agent comprises HTF. 
     
     
         7 . The system of  claim 1 , wherein the first stabilizing agent comprises SSS. 
     
     
         8 . The system of  claim 1 , wherein the second stabilizing agent comprises HTF. 
     
     
         9 . The system of  claim 1 , wherein the second stabilizing agent comprises SSS. 
     
     
         10 . The system of  claim 1 , wherein the cryoprotectant comprises DMSO, ethylene glycol, propylene glycol, or glycerol, alone or in combination. 
     
     
         11 . The system of  claim 1 , wherein the dehydrating agent includes sucrose. 
     
     
         12 . The system of  claim 1 , wherein the dehydrating agent includes dextrose. 
     
     
         13 . The system of  claim 1 , wherein the dehydrating agent includes trehalose. 
     
     
         14 . The system of  claim 1 , wherein the dehydrating agent includes lactose. 
     
     
         15 . The system of  claim 1 , wherein the dehydrating agent includes raffinose.