The improvement of biocompatibility by incorporating porphyrins into carbon dots with photodynamic effects and pH sensitivities

Photodynamic therapy (PDT) is a promising new treatment for cancer; however, the hydrophobic interactions and poor solubility in water of photosensitizers limit the use in clinic. Nanoparticles especially carbon dots have attracted the attention of the world’s scientists because of their unique properties such as good solubility and biocompatibility. In this paper, we integrated carbon dots with different porphyrins to improve the properties of porphyrins and evaluated their efficacy as PDT drugs. The spectroscopic characteristics of porphyrins nano-conjugates were studied. Singlet oxygen generation rate and the light- and dark-induced toxicity of the conjugates were studied. Our results showed that the covalent interaction between CDs and porphyrins has improved the biocompatibility. The synthesized conjugates also inherit the pH sensitivity of the carbon dots, while the conjugation also decreases the hemolysis ratio making them a promising candidate for PDT. The incorporation of carbon dots into porphyrins improved their biocompatibility by reducing toxicity.