Scheme 1.

Schematic illustration of supramolecular PTA formed by the host-guest complexation between SAC4A and IR780. The encapsulation of IR780 with SAC4A gives rise to the solubility, photostability and photothermal conversion improved, but the fluorescence annihilated. Upon reaching the tumor tissue, the host responses to the hypoxia microenvironment, leading to the release of IR780 with fluorescence recovered. The supramolecular nanoformulation IR780@SAC4A therefore achieves tumor-selective imaging and PTT concurrently.