Carbon dots-based novel photosensitizers

An ideal photosensitizer of photodynamic therapy (PDT) should efficiently generate and utilize reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced in situ. We have designed and synthesized a series of carbon dots (CDs) based photosensitizers with excellent photosensitivity and biosafety. These CDs can accurately target lysosomes, mitochondria, and RNA in the tumor cells, thereby efficiently generating ROS or RNS to induce cellular autophagy, apoptosis, and pyroptosis. Moreover, the synthesized photo-/sono-sensitive CDs exhibited efficient ROS generation under red-light irradiation and low-intensity pulsed ultrasound stimulation. This significantly improved the tumor therapeutic efficacy by combining PDT and sonodynamic therapy (SDT). Additionally, these CDs exhibit outstanding fluorescent imaging capabilities, making them a promising tool for bioimaging applications. Based on these attributes, PDT can specifically target organelles with high precision while maintain good biosafety properties. In short, CDs have strong potential to be developed into the next generation photosensitizers.