Why is Blood Red?

Researchers from the Institute for Mummies and the Iceman, Italy, have used a cutting-edge nanotechnology to discover red blood cells in a 5300-year-old mummy.

The ancient mummy, named Oetzi, was discovered frozen with an arrow in his back in the Italian Alps in 1991. Previous work by Dr Albert Zink and his colleagues at the Institute for Mummies and the Iceman revealed that a wound in Oetzi’s hand contained haemoglobin, the molecule in red blood cells that carries oxygen.

In his latest work, Dr Zink collaborated with material scientists from Darmstadt Technical University to investigate whether intact blood cells were present in Oetzi’s hand wound. The group used an atomic force microscope to investigate thin tissue sections. This instrument drags a miniscule metal tip, only a few atoms in diameter, across a sample of tissue and measures how much it moves. The results allow researchers to build up a three-dimensional map of the particles in the sample. Analysis using the atomic force microscope revealed the biconcave disc shape – that of red blood cells – in a sample taken from Oetzi’s hand wound.

Examining mummies with cutting-edge techniques, such as the atomic force microscope, allows scientists to build large amounts of information about their ancient subjects, ranging from genetic relationships to diets and diseases.

Glossary
Biconcave disk
flattened circular shape of a healthy red blood cell, it looks rather like a doughnut.