The Modern Laboratory · The Modern Papers

The Modern Papers · MP·04 · 1985

1985: Freezing without ice

Rall and Fahy found a way to stop water turning to ice at all. It is now how most eggs and embryos are stored.

The story

Slow freezing, the method behind the first frozen-embryo babies (FP·07 to FP·09), lets ice form outside the cell and draws water out of it gently. William Rall and Gregory Fahy, at the American Red Cross laboratory in Bethesda, Maryland, asked whether ice could be avoided altogether.

They used a solution of cryoprotectants so concentrated that, cooled quickly, it set into a clear glass. Mouse embryos held this way at minus 196°C survived in high proportions.

The method is called vitrification. Twenty years later it reached the human egg in its modern form (MP·12), and it is now the method most IVF laboratories use.

“embryos seem to survive in high proportions after cryopreservation in the absence of ice.”From the paper's abstract

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