To achieve this type of gene shutdown, known as RNA interference, many researchers have tried — with some success — to deliver RNA with particles made from polymers or lipids. However, those materials can pose safety risks and are difficult to target, says Daniel Anderson, an associate professor of health sciences and technology and chemical engineering, and a member of the David H. Koch Institute for Integrative Cancer Research at MIT.

The new particles, developed by researchers at MIT, Alnylam Pharmaceuticals and Harvard Medical School, appear to overcome those challenges, Anderson says. Because the particles are made of DNA and RNA, they are biodegradable and pose no threat to the body. They can also be tagged with molecules of folate (vitamin B9) to target the abundance of folate receptors found on some tumors, including those associated with ovarian cancer — one of the deadliest, hardest-to-treat cancers.

Anderson is senior author of a paper on the particles appearing in the June 3 issue of Nature Nanotechnology. Lead author of the paper is former MIT postdoc Hyukjin Lee, now an assistant professor at Ewha Womans University in Seoul, South Korea.