Selenium Vacancy Engineering Using Bi₂Se₃ Nanodots for Boosting Highly Efficient Photonic Hyperthermia

Despite bismuth-based energy conversion nanomaterials having attracted extensive attention for nanomedicine, the nanomaterials suffer from major shortcomings including low tumor accumulation, long internal retention time, and undesirable photothermal conversion efficiency (PCE). To combat these challenges, bovine serum albumin and folic acid co-modified Bi₂Se₃ nanomedicine with rich selenium vacancies (abbreviated as V_Se-BS) was fabricated for the second near-infrared (NIR-II) light-triggered photonic hyperthermia. More importantly, selenium vacancies on the crystal planes (0 1 5) and (0 1 11) of V_Se-BS with similar formation energies could be distinctively observed via aberration-corrected scanning transmission electron microscopy images. The defect engineering endows V_Se-BS with enhanced conductivity, making V_Se-BS possess outstanding PCE (54.1%) in the NIR-II biowindow and desirable photoacoustic imaging performance. Tumor ablation studies indicate that V_Se-BS possesses satisfactory therapeutic outcomes triggered by NIR-II light. These findings give rise to inspiration for further broadening the biological applications of defect engineering bismuth-based nanomaterials.