Cells (image) Johns Hopkins Medicine Share Print E-Mail Caption Left to right: Images of an early, three day-old human embryo, five day-old human embryo, a colony of the new 3i human ESC cells developed by the Zambidis laboratory, and a colony of a conventional human ESC, which is developmentally more mature. Human ESC colonies are stained for nuclei (blue), the stem cell marker OCT4 (red), and the stem cell marker TRA-1-81 (green). Credit Elias Zambidis and Yulian Zhao Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.