Body-clearable chromium nitride for synergetic photothermal and photodynamic treatment

Phototherapy is one of most promising antitumor alternatives that realizes the photoablation of solid tumors with the help of photoactive materials. However, the long-term in vivo toxic potential of the non-degradable photoactive material hinders it from clinical applications. In this work, a body-clearable nanomaterial of chromium nitride was applied for synergetic phototherapy. Chromium nitride is a broad-spectra near infrared (NIR) absorbent that can be excited by NIR to generate hyperthermia and reactive oxygen species (ROS) simultaneously. As a result, the dual actions of photothermal and photodynamic treatment outcomes could be achieved by this single matter. The in vitro cell experiments proved a better antitumor outcome of the synergetic phototherapy action over the single-role photothermal or photodynamic therapy. More interestingly, in vivo metabolic studies disclosed that the overall in vivo content of chromium nitride dropped significantly after intravenous injection, and the excretion of chromium nitride was found in urine and feces. Consequently, this work presents a new idea for precise and low side-effect phototherapy modality.