New York (PTI): Blood donations could one day be a thing of the past -- thanks to scientists who have grown the first functional red blood cells in the laboratory from human embryonic stem cells (ESCs). Researchers had previously grown blood cells from ESCs but never achieved the "enucleation" step which means that the cells can't divide and become cancerous.

Now, a team in the US created the red blood cells by exposing cultures of human ESCs to sequence of nutrients and growth factors -- this turned them first into haemangioblasts, precursors to blood cells, and then into mature blood cells.

According to the scientists, the crucial achievement was getting the cells to expel their nuclei just as they would in the body. "Experts said it was impossible, and we're pretty surprised ourselves when it worked," said Robert Lanza. Lanza is Chief Scientist at Advanced Cell Technology, the company which grew red blood cells in collaboration with researchers at the Mayo Clinic in Rochester and the University of Illinois in Chicago.

Subsequently, tests on the red blood cells suggested that they can deliver oxygen just as efficiently as donated red blood cells. The team was also able to produce the red blood cells in bulk, creating populations of as many as 100 billion cells, the 'New Scientist' reported. "You wouldn't have to worry about shortages because you could create as many as you want. Stem-cell-derived blood would also eliminate the risk of transmitting the pathogens that cause hepatitis and HIV through transmissions," according to the researchers.

The findings have been published in the latest edition of the 'Blood' journal.