Ultralong-Circulating and Self-Targeting "Watson-Crick A = T"-Inspired Supramolecular Nanotheranostics for NIR-II Imaging-Guided Photochemotherapy.

A carrier-free theranostic nanodrug directly coassembled using a NIR probe and a chemotherapeutic drug is a promising alternative for cancer theranostics. Nevertheless, this nanodrug still faces the limitations of short blood circulation and inefficient tumor accumulation/tumoral cellular uptake in vivo. Meanwhile, most exogenous targeting ligands and poly(ethylene glycol) have no therapeutic effect. Herein, we designed an ultralong-circulating and self-targeting nanodrug by an ordered supramolecular coassembly of indocyanine green (ICG), methotrexate (MTX, chemotherapeutic drug and cancer-cell-specific ligand), and clofarabine (CA). Notably, CA, as a surfactant-like chemotherapeutic drug, was introduced into the initial ICG-MTX coassembly by "Watson-Crick A = T-inspired" hydrogen-bond-driven sequential assembly with MTX. This carrier-free theranostic nanodrug with exceptionally high drug payload (100 wt %) not only showed superior serum stabilities but also displayed ultralong blood circulation (>7 days), enabling efficient accumulation at tumor sites. Moreover, our nanodrugs could be self-recognized by cancer cells and release the drugs on demand through lysosomal acidity and external laser stimulus. Under NIR-II imaging guidance, high-efficiency tumor ablation via synergistic photothermal-chemotherapy could be achieved in one treatment cycle while preventing the tumor recurrence. Our ultralong-circulating and self-recognizing carrier-free theranostic nanodrug based on the "drug-delivering-drug" strategy might have the potential for clinical theranostic application.