Double-Lock Superpolymer TDN is Used for the Theranostics of HCC

Abstract Hepatocellular carcinoma (HCC) is difficult to diagnose early and treat effectively due to its heterogeneity and lack of highly specific biomarkers. Here, we develop a double-lock superpolymer tetrahedral DNA (TDN) integrated with small extracellular vesicles (SUPDIA) for HCC theranostics. The TDN incorporates an HSP70 aptamer and a miR-21 complementary sequence, both initially blocked to form a locked state. Upon dual-target recognition of HSP70 and miR-21, two sticky ends are exposed, inducing TDN super-assembly into superpolymers with aggregated Cy5 fluorescence and concurrent miR-21 sequestration. This system enables dual-target-dependent signal amplification, achieving specific HSP70 detection with a 0.01#x2212;10 ng/mL linear range and a 0.001 ng/mL detection limit. HepG2 cell-derived small extracellular vesicles (sEVs) are used to encapsulate TDNs, conferring homotypic targeting, caveolin-dependent uptake, lysosomal escape, and deep penetration in 3D spheroids. In vivo, SUPDIA shows enhanced fluorescence in HCC xenografts and superior imaging versus non-aggregating controls, while effectively downregulating miR-21, inhibiting angiogenesis, and reducing cell viability. This exosome-delivered TDN superpolymer offers a precise, biomarker-guided platform for integrated HCC diagnosis and therapy.