An experimental preservation method could let
women store eggs at home as a powder and then 'just add water' (and sperm) when needed. The Israeli biotechnology firm Core Dynamics has reported that 23
of 30 cow eggs were viable after a trial using their process, which has not yet been tested on human
Currently, eggs are frozen (or, increasingly, 'vitrified') and stored at a fertility clinic. This is often expensive, with
an initial cost of around £3,500 and then a further yearly storage cost. According
to a report in New Scientist, the firm claims that their process could
dramatically cut initial costs and avoid storage fees altogether, as the powder
would only need to be stored in a dark, vacuum-packed container.
The process uses the same ultra-rapid
cooling technique as vitrification but before this soaks the egg in a solution
which helps to prevent cold damage to the tissue. Normally, after vitrification, eggs are stored in liquid nitrogen. But, New Scientist relates, in Core
Dynamics' technique 'residual frozen water is
converted directly into a gas by storing the vitrified cells at -55°C for
a day under low pressures, which allows the water to sublime away'. The
resulting powder would then be stored before use at a later date.
The scientist who developed this method, Dr Amir
Arav, revealed his findings at the Cryo conference in Berlin, Germany, saying
that the powder can potentially be stored indefinitely. The method has already
been tested successfully on red blood cells and on human mononuclear cells from
umbilical cord blood.
But the process requires much more testing before
it can be used for human fertility preservation. Claus Andersen, professor of
human reproductive physiology at the University Hospital of Copenhagen,
Denmark, told New Scientist: 'We need to know whether the oocytes can be
fertilised after freeze-drying, whether they then form normal embryos, and if
they do, the extent to which they implant in the womb and develop into healthy
firm hope to use the rehydrated eggs to produce viable and healthy animals,
before potentially moving on to using human eggs. Professor Anderson says that 'the freeze drying needs to be shown to be as good as the conventional method
of freezing under liquid nitrogen and this could take some time'.