Research groups led by Botond Roska at the Friedrich Miescher Institute for Biomedical Research (FMI) and Daniel Müller at the ETH Zurich Department of Biosystems Science and Engineering (D BSSE) have developed a novel method that allows them to efficiently deliver genes into single cells in whole tissues. This not only facilitates the study of the individual cells in an organ such as the brain, but could also pave the way to new gene therapies.