Optimized DNA "Nanosuitcases" for Encapsulation and Conditional Release of siRNA.

We set out to design, synthesize, and optimize a DNA-minimal cage capable of encapsulating oligonucleotide drugs to facilitate their delivery. Through rational design and optimization using in vitro assays, we have assembled the first DNA "nanosuitcase" that can encapsulate a siRNA construct and release it upon recognition of an oligonucleotide trigger. The latter may be a mRNA or a microRNA (miRNA) which offers potential for dual or synergistic therapy. This construct assembles in near 100% yield, releases its cargo on demand, and can sustain biological conditions. Moreover, we find that the DNA scaffold is able to protect its cargo against site-specific cleavage and nuclease degradation. Release of the cargo is performed with fixed cells using a FRET-enabled construct imaged by confocal microscopy and reveals that the DNA cage remains responsive at the molecular level in a complex cellular environment. We foresee this construct will be able to address challenges in drug delivery, more specifically in nontoxic delivery and targeted release.