(IMAGE) Institute of Science and Technology Austria Caption Illumination of human cells in freely-designed patterns (here depicting the letters IST) demonstrates the new ability to control selected cells among many other cells. Notably, all cells are genetically identical and differ only whether light was applied to them or not. Here, spatial activation of a reporter gene in HEK293 cells was triggered with light-activated receptor tyrosine kinases. Scale bar: 10 mm. (Illustration quality enhanced). Credit © IST Austria Usage Restrictions None License Licensed content 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.