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.