Inosine Incorporation in DNA Nanostructures and 3D DNA Crystals

DNA nanotechnology is based on programmable base pairing, resulting in the precise construction of nanoscale structures. Sequence variability in DNA self-assembly is achieved by the use of xenonucleic acids, chemically modified bases, and base analogues. The naturally occurring base inosine, while well-studied in RNA editing, has not been used in the context of DNA nanotechnology. Here, I demonstrate the use of inosine in DNA nanostructures, specifically by incorporating inosine within the duplex regions or junctions of a double-crossover DNA motif. In strand displacement and competition assays, canonical complements do not displace inosine-containing strands postassembly but dominate in product formation when competing with inosine-containing strands during assembly. Finally, sticky ends with inosine base pairs enable the formation of rationally designed 3D DNA crystals based on the tensegrity triangle motif. Overall, this work shows that inosine is a useful addition to the library of sequence variations in DNA nanotechnology.