Porphyrin-Derived Carbon Dots for Red-Light Activated Photodynamic Therapy of Breast Cancer

In recent years, cancer has emerged as a major global health threat, ranking among the top causes of mortality. While treatments such as surgery, immunotherapy, radiation therapy, and chemotherapy remain widely used, photodynamic therapy has been gaining significant interest. Most of the photosensitizing agents employed in clinical settings are derived from tetrapyrrolic frameworks, including porphyrins, chlorins, and phthalocyanines. Although these compounds have demonstrated therapeutic effectiveness, they suffer from critical drawbacks, such as limited solubility in water and inadequate (photo)stability. To address these issues, herein, the formulation of the previously reported and promising photosensitizer tetrakis(4-carboxyphenyl) porphyrin into carbon dots is reported. The carbon dots were found with enhanced aqueous solubility, high (photo)stability, and greater singlet oxygen quantum yield overcoming the limitations of the molecular photosensitizer. While being nontoxic in the dark, the carbon dots induced a phototherapeutic effect in breast cancer cells and multicellular tumor spheroids.