Topological Single-stranded DNA Encoding and Programmable Assembly of Molecular Nanostructures for NIR-II Cancer Theranostics

Molecular nanotechnology promises to offer privileged access to developing NIR-II materials with precise structural and functional manipulation for transformable theranostic applications. However, the lack of an affordable, yet general, method makes this goal currently inaccessible. By virtue of the intriguing nucleic acid chemistry, here we present an artificial base-directed topological single-strand DNA encoding design that enables one-step synthesis of valence-controlled NIR-II molecular nanostructures and spatial assembly of these nanostructures to modulate their behaviors in living systems. As proof-of-concept studies, we construct ultrasmall Ag2S quantum dots and pH-responsive, size-tunable CuS assemblies for in vivo NIR-II fluorescence imaging and deep tumor photothermal therapy. This work paves a new way for creating functionally diversified architectures and broadens the scope of DNA-encoded material engineering. An artificial base-directed topological DNA-encoding strategy is reported as a versatile platform for engineering NIR-II nanomedicine with programmable assembly and precise control over composition and surface valence. Proof-of-principle studies were performed to engineer Ag2S-DNA QDs and CuS-DNA nanodots, demonstrating strong emission or absorption in the NIR-II window favorable for applications in bioimaging and deep-penetration tumor therapy.image