The Breakthroughs
The strategy that has been used for penetration of early-stage embryos during the past 50 years or more depends on compression of the embryo between a holding pipette and a sharp glass injection pipette, presented from exact opposite directions. This strategy depends on the presence of an intact early zona. It is the structure of the zona, its resistance to deformation, which makes this possible. After the embryo escapes from the zona (a process called “hatching”), only the GeneSearch Embryo Cradle can hold and penetrate it easily.
This capability of the GeneSearch system to hold and puncture later-stage embryos is significant because human reproduction scientists now know that biopsy at a later stage provides a DNA analysis that is more useful for PGD (pre-implantation genetic diagnosis). For more dependable accuracy, the target stage for biopsy of human embryos has been pushed back a few cell division cycles, until the time just preceding natural hatching. Because the zona is thinner on these expanded blastocysts, the compression strategy for penetration is not effective or dependable.
For that reason, the accepted best procedure for biopsy of pre-implantation human embryos requires a grazing shot with a laser, to make a trench across the zona so cells can be obtained for analysis. Cells can be damaged by heat, or the embryo can hatch prematurely in the culture dish after the zona is cut by the laser shot. Once an embryo is hatched, there is no good standard procedure or tool for water volume reduction to improve freezing results, until now.
The GeneSearch Embryo Cradle allows biopsy of pre-implantation embryos at a later stage of development, right up to the time for implantation in the uterus. Then, after collection of a few cells for DNA analysis, even as part of the same procedure, this device can easily remove the contained blastocoel fluid to optimize the freezing process.
Equine Applications
Dr. Taylor invented the Embryo Cradle to remove the water-solution contained inside llama embryos so they could be frozen successfully for the first time. The two live llama babies he produced from frozen embryos were and are still the only two in history. Now it has been shown that the Embryo Cradle is also the tool of choice for removing water solution from equine embryos, permitting successful freezing of horse embryos larger than 300um. (See this ground-breaking research paper by Fabian Diaz, published in Theriogenology) This is very significant for many reasons, but especially because international movement of animal embryos is limited to those that can be frozen and held in liquid nitrogen for at least the period of incubation of any diseases that they might carry.
The Embryo Cradle permits total volume reduction of equine embryos without damage to the delicate capsule that surrounds them, and easy collection of the blastocoel fluid removed. This may be important because early indications are that there is enough DNA in that fluid for determination of gender and possibly of many genetic characteristics of the foal the embryo will become.
Beyond that, the Cradle can be used for ICSI, the injection of a single sperm into the equine oocyte to create a viable embryo, and two of our Research Licensees are working to document that capability. GeneSearch is actively seeking to sell the company or the patent rights for equine embryology to one of the major players in the equine scene as part of our strategy for commercialization of the Embryo Cradle.
