Hematoporphyrin Photosensitizer-Linked Carbon Quantum Dots for Photodynamic Therapy of Cancer Cells

The direct use of conventional photosensitizers in photodynamic therapy (PDT) of cancer cells has been thwarted by their low solubility, poor photostability, and aggregation tendency. Hence, complex and hectic synthetic procedures, such as developing nanomaterials and subsequently loading them with photosensitizers, have become mandatory for the effective use of photosensitizers in PDT. In this study, we have avoided complex procedures and produce hematoporphyrin (HP) photosensitizer-encapsulated carbon quantum dots (CQDs) (HP-CQDs) facilely through a well-controlled one-step microwave reaction by using the HP monomer as one of the precursors. The as-synthesized HP-CQDs retained all intrinsic optical and chemical properties of HP, while displaying excellent solubility in water. Importantly, the excellent reactive oxygen species generation ability of HP-CQDs under the illumination of deep red light favored their applicability in PDT-assisted efficient eradication of human breast cancer cells (MCF-7). Compared to HP, HP-CQDs exhibited very high phototoxicity and low dark toxicity toward MCF-7 cells. Overall, this study offers a proof of concept that photosensitizer-implanted CQDs, having excellence in PDT-assisted cancer treatment, can be easily designed by strategically exploiting the diversity available in the selection of precursors and synthesis conditions to produce CQDs.