Image: Albert Zink
You're looking at the world's oldest red blood cell: it was found in the body of the 5,300-year old Ötzi the Iceman mummy.
Albert Zink, a biological anthropologist at the European Academy of Bozen/Bolzano, was the leader of the study that uncovered the elusive cells. "It was very surprising, because we didn't really expect to find compete red blood cells," Zink said. "We hoped to find maybe some remnants or shrunken red blood cells, but these are looking like a modern-day sample; the dimensions are the same."
Zink and his colleagues took tissue samples from Ötzi's arrow wound and from an earlier wound on the mummy's hand. Using a light microscope, they identified round objects that looked a bit like red blood cells, Zink said. But to be sure, the researchers needed more advanced technology.
They turned to a device called an atomic force microscope, which works by "feeling" rather than "seeing" an object. The minuscule probe, itself invisible to the naked eye, runs over the object like a needle on a record player. As the probe bumps up and down along the object's contours, a laser measures the movement. The result is a three-dimensional "tracing" of the object.
In the case of the mysterious Ötzi contents, an exciting picture emerged: The roundish shapes were indeed red blood cells.