pH-Dependent Cancer-Directed Photodynamic Therapy by a Water-Soluble Graphitic-Phase Carbon Nitride-Porphyrin Nanoprobe.

Theranostic photodynamic nanomaterials suffer from poor water solubility and nontargeted toxicity. A water-soluble graphitic-phase carbon nitride-based material (g-C N ) conjugated to a positively charged porphyrin P2 (conjugating concentration: 60 μm mg  mL ) is shown to be a new concept of photodynamic therapeutic agent (g-C N -P2). The pH-sensitive emission of g-C N is the driving force for the generation of O from g-C N -P2. The amount of O /light generated from a photosensitizer porphyrin can be controlled by the pH-sensitive emission of g-C N at acidic pH (pH 4-6), especially under acidic conditions mimicking those of tumor tissue, and thus has the potential to be utilized as a cancer-selective PDT agent.