Nanotechnology researchers have known for years that RNA, the cousin of DNA, is a promising tool for nanotherapy, in which therapeutic agents can be delivered inside the body via nanoparticles. But the difficulties of producing long-lasting, therapeutic RNA that remains stable and non-toxic while entering targeted cells have posed challenges for their progress. Now, researchers detail successful methods of producing large RNA nanoparticles and testing their safety in the delivery of therapeutics to targeted cells.