A Nature Biomedical Engineering study described a non-viral strategy to edit human blood stem cells inside the body using targeted lipid nanoparticles. Published by Zhiwei Luo, A.T. Zhu, and Michael J. Mitchell’s team, the work focuses on delivering gene-editing machinery to haematopoietic stem cells in vivo rather than relying on viral vectors, addressing one of the major hurdles in systemic editing.