The development of RNA-based nanostructures and their use in a variety of applications, including RNA interference (RNAi) and drug delivery, represents an emerging field of science, technology, and biomedicine. RNA is a dynamic material because of its natural functionalities, its ability to fold into complex small structures, and its capacity to self-assemble. Taking advantage of these characteristic, NCI Researchers have improved upon their existing invention of multi-functional RNA/DNA nanoparticles by adding a RNA toehold instead of a DNA toehold. In in vitro studies, they have shown that the nanoparticles are capable of inhibiting HIV-1 gene expression in Hela cells transfected with a HIV-1 infectious clone and GFP expression in MDA-MB231 breast cancer cell lines transfected with eGFP.