Stable self-assembling nucleic acid nanostructures comprising: • a plurality of oligonucleotides, • a plurality of G-quadruplex forming nucleic acids linked to the plurality of oligonucleotides, and • a plurality of G-quadruplex stabilizing domains linked to the G-quadruplex forming nucleic acids. The nucleic acid nanostructures are suitable for use as as agonists or antagonists of nucleic acid interacting complexes, such as Toll-like receptors； for inhibiting DNA or RNA expression； for stimulating or inhibiting an immune response； and for treating diseases such as cancer, infectious diseases, allergies and allergic diseases, and autoimmune diseases.
