Carambola-like Bi2Te3 superstructures with enhanced photoabsorption for highly efficient photothermal therapy in the second near-infrared biowindow

Photothermal therapy (PTT) stimulated by light in the second near-infrared (NIR-II) biowindow shows great superiorities in the penetration ability of tissue and maximum permissible exposure (MPE). Exploring new photothermal agents with good optical absorbance in the NIR-II region is highly desirable for efficient cancer therapy. Herein, we successfully prepare carambola-like bismuth telluride (Bi2Te3) superstructures modified with PEGylated phospholipid (Bi2Te3@PEG) for CT imaging-guided PTT in the NIR-II biowindow. Attributing to their superstructures, Bi2Te3@PEG exhibited enhanced photoabsorption with higher photothermal conversion efficiency (55.3% for 1064 nm) compared with that of Bi2Te3 nanoparticles. Furthermore, the good X-ray attenuation capacity of Bi endows Bi2Te3@PEG with an outstanding performance as computed tomography (CT) contrast agents. Bi2Te3@PEG superstructures have been confirmed to effectively eliminate tumor in vitro and in vivo with negligible long-term toxicities, offering them great potential to act as theranostic platforms for cancer diagnosis and treatment.