Biocompatible small organic molecule phototheranostics for NIR-II fluorescence/photoacoustic imaging and simultaneous photodynamic/photothermal combination therapy

The integrated functionalities of multiple diagnostic and therapeutic modalities in a single phototheranostic nanoplatform have been validated as a significant breakthrough toward cancer theranostics. Nevertheless, most reported nanoplatforms are constructed by using complex components through difficult fabrication processes, and often need different excitation wavelengths. Herein, a novel small-molecule dye, DPP-BDT, with absorption in the NIR-I window and fluorescence emission in the NIR-II region was designed and synthesized, and it presented excellent photodynamic and photothermal performance. Based on single component DPP-BDT, multifunctional phototheranostics were rationally and successfully constructed. From in vitro and in vivo experiments, such nanotheranostics showed excellent tumor destruction abilities under a single wavelength of laser irradiation, benefiting from the NIR-II fluorescence/photoacoustic dual-modal imaging guided photodynamic/photothermal combination therapy.