Leveraging the potential of carbon: carbon quantum dots as a versatile probe for cancer diagnosis and treatment

In the global plane, cancer calls for creative strategies for diagnosis and treatment. Carbon quantum dots (CQDs) have emerged as a novel material for the field of cancer theranostics, showing their distinguishing features: biocompatibility, easy surface functionalization, and controllable fluorescence. Compared with semiconductor quantum dots, carbon-based fluorescent nanocrystals, called CQDs typically under 10 nm in size, are easier to synthesize and much less toxic. This paper reviews the synthesis, characterization and applications of CQDs synthesized from biomolecules and medicinal plants, which may be used to treat cancer. Depending on the method, several techniques have been developed for the synthesis of CQDs. Laser ablation, electrochemical oxidation, hydrothermal treatment and microwave synthesis are among the techniques developed for this purpose. Characterization techniques assist in gathering detailed information related to the structural and optical characteristics of CQDs. The review also discusses the challenges of CQDs and their future prospects by underlining the need for further research work to cope with the issues of toxicity, biocompatibility, and delivery specifically to the brain. Overall, the review holds enormous potential to revolutionize cancer treatment through a theranostic approach that combines diagnosis, imaging, and therapy. Keywords: Carbon quantum dots, cancer, photodynamic therapy