Dr Paul de Souza and scientists at the Roslin Institute have successfully created human cells without using animal products.
In the past there has been concern that the animal products used in stem cell development could contaminate them.
In the procedure currently used, embryonic stem (ES) cells are cultivated in "feeder layers" consisting of a nutrient material derived from live animal cells. Embryonic stem cells have the ability to become any kind of tissue, and scientists hope they can one day be used to treat a range of diseases. Animal derived serum has also been used and this means there is a theoretical risk of viruses and other harmful agents being transmitted from the animal cells to the stem cells, and thus on to patients who receive stem cell therapy.
Scientists at the Roslin Institute successfully used human cells instead by using isolated stem cells from embryos created, but not needed, for IVF treatment.
The cells were then placed on a layer of human protein called laminin, which is the material that separates growing human cells from each other.
They then used "feeder" layers of human neonatal foreskin cells to provide the nutrients and growth factors normally supplied by mouse feeder cells.
Four new cultures of embryonic stem cells were established by this method; three, as is usual, were given additional growth factors and nutrients derived from cows; the fourth was given a mixture composed completely of human growth factors and proteins.
This made it the first embryonic stem cell line not directly exposed to any animal products at any stage. Dr de Souza said.
The fact that the foreskin cells had been exposed to animal products during their production still meant a possibility exists that unknown pathogens could have been transferred through these helper cells to the stem cells themselves.
Another team of researchers at the IVI Foundation in Valencia, Spain, have carried out similar research using placental skin-like cells instead of the foreskin cells used by the Edinburgh team.
Scientists at Advanced Cell Technology in Massachusetts, US, have also produced embryonic stem cells without using any feeder cells.