A report published this week in Nature Nanotechnology describes a new method for delivering a genetic treatment called a short interfering RNA, or siRNA, which can turn off, or silence, a gene.

The sequence of an siRNA determines which gene it regulates. In theory, siRNAs could be a powerful therapeutic tool, silencing just about any human gene that has gone haywire in cancer or other disease. However, delivering the siRNAs to the right place in the body continues to be a challenge.

A team of researchers at the Massachusetts Institute of Technology, Harvard Medical School and Alnylam Pharmaceuticals built a three dimensional tetrahedron from six short pieces of DNA. They then glued RNA molecules to each edge and added small molecules to help target the complex to tumor cells. When injected into a mouse that had been implanted with human tumors, the nanoparticles accumulated at the tumor site and reduced the function of a gene that made the implanted tumors glow.

A comment on the work published in Nature Nanotechnology described the new method for delivering siRNAs to tumor cells a “metaphorical foot in the slowly closing door on siRNA therapeutics.”