Smart Acid-Activatable Self-Assembly of Black Phosphorous as Photosensitizer to Overcome Poor Tumor Retention in Photothermal Therapy

Nanomaterials-based photothermal therapy (PTT) could efficiently eliminate cancer cells in a noninvasive manner. However, nanoscale photosensitizers still suffer from several drawbacks, limiting them from being an ideal PTT approach against cancer. These include unfavorable biodistribution and poor retention in tumor tissue. In this study, acid-activatable smart self-assembly of black phosphorous (BP) and polyoxometalates (POM) is carried out to yield POM@BP with prolonged tumor retention and enhanced efficacy of PTT. The as-rationally designed POM@BP photosensitizers in acidic tumor microenvironments self-assemble into nanoparticles with larger sizes, remarkably increasing the light absorption ability of BP nanosheets in PTT of cancer. The as-obtained POM@BP endows prolonged retention and enhances the photothermal response in tumor tissue by smart self-assembly of BP into larger nanoparticles. In summary, the proposed potent approach for the rational design and tailor photosensitizer for cancer treatment looks very promising for future scientific breakthroughs in nanomedicine.