Theranostic nanosystem with supramolecular self-assembly for enhanced reactive oxygen species-mediated apoptosis guided by dual-modality tumor imaging.

With the development of precision medicine, visual and traceable treatments are highly desirable for cancer therapy. However, researchers and clinicians remain confused regarding where the drug distributes and location of the tumor, when the drug is released and when to irradiate the tumor, and how the drug presents antitumor activity, all of which hinders assessment of the cancer patient's condition and formulation of a follow-up treatment scheme for clinicians. Here, a supramolecular self-assembly theranostic nanosystem (MWNs) was designed for enhanced reactive oxygen species (ROS)-mediated cell apoptosis guided by dual-modality tumor imaging. Specifically, merocyanine was introduced in cyanine dye to extend its conjugated π-scaffolds, which could preferentially self-assemble into nanovesicles owing to its amphipathy. Furthermore, withaferin A (WA), used as a chemotherapeutic drug, was loaded to construct MWNs. The assembled or disassembled MWNs behaved differently in photoacoustic (PA) intensity and fluorescence signal intensity. The MWNs exhibited stronger PA signals and quenched fluorescence, which monitors their distribution and images the tumor location in vivo, while the disassembled MWNs showed weak PA signals and recovered fluorescence, indicating the release of drug and instructing the appropriate time to irradiate for photodynamic therapy (PDT). Thus, ROS generation introduced by PDT and released WA led to cell apoptosis. This intelligent nanosystem for precise cancer therapy that reveals where the tumor is, when to irradiate the tumor, and how the tumor is cured might establish the basis for biomedical applications of finely controlled platform.