Kissing loop-mediated fabrication of RNA nanoparticles and their potential as cellular and in vivo siRNA delivery platforms

We describe an efficient method to condense RNAs into tightly packed RNA nanoparticles (RNPs) for biomedical applications without hydrophobic or cationic agents. We embedded kissing loops and siRNA in the RNAs to constrain the size of RNPs to 100 nm, making them suitable not only for cellular uptake but also for passive tumor accumulation. The resulting RNPs were efficiently internalized into cells and downregulated the target gene of siRNAs. When intravenously injected into tumor-bearing mice, RNPs could also accumulate in the tumor. The reported fabrication method could be readily adopted as a platform to prepare RNPs for and delivery of bioactive RNAs.