Human Stem Cell  2015 

Silvia Ferreira, Cristina Lopo and Eileen Gentleman

Kings' College London.

The following information about the winning image comes from the Wellcome Image Awards website:

A single human stem cell, which has a natural ability to repair damaged tissue and can divide to produce some of the different cells found in the body. This cell is sitting in a mixture of chemicals designed to mimic its natural environment inside the body, so that researchers can better understand how it interacts with its surroundings. 

The stem cell is from inside the hip bone of a healthy person who donated some bone marrow to help treat patients who develop complications after receiving a marrow transplant. 

The diameter of the cell is approximately 15 micrometres (0.015 mm). 

Imaging technique: cryogenic scanning electron microscopy

The sample was first rapidly frozen at cryogenic temperatures (lower than −150°C or −238°F) to preserve it in its native, water-containing environment. Electrons were then bounced off the surface of the frozen sample to provide information on its structure. This information was used to create a greyscale replica of the cell, which was then digitally coloured.