Photodynamic Action of Single-Walled Carbon Nanotubes

Photodynamic therapy is achieved by the combination of photosensitizers, harmless visible or near-infrared (NIR) light, and molecular oxygen (O₂). Photosensitizers transfer their absorbed light energy to O₂ to generate a major active species in photodynamic therapy, singlet oxygen. In this review, I will discuss the possibility of single-walled carbon nanotubes as NIR photosensitizers, while explaining the general photophysics and photochemistry underlying photodynamic therapy as well as summarizing recent advances in the purification technologies for single-walled carbon nanotubes to reduce their toxicity concerns.