Hairpin-functionalized DNA tetrahedra for miRNA imaging in living cells via self-assembly to form dendrimers

DNA self-assembling nanoprobes with self-transferability and resistance to nuclease degradation have been developed and applied to live cell bio-imaging. In this work, we constructed a hairpin-functionalized DNA tetrahedron (HFDT) intramolecular catalytic self-assembly platform to detect low-abundance miRNAs by a catalyzed hairpin assembly (CHA). The designed HFDT enhances the CHA reaction efficiency and aggregates into dendrimer structures in the presence of miRNAs. This innovative "small to large" strategy can effectively change the distribution and properties of biomaterials in the organism, thus effectively retaining them inside the tumor and reducing the efflux of nanomaterials, increasing their accumulation in the tumor site and protecting them from the complex physiological environment, which has promising applications in tumor imaging.