Carbon dots derived from natural medicines: Therapeutic advances and challenges

Carbon dots (CDs) are a novel nanomaterial exhibiting exceptional biocompatibility, tunable fluorescence, and versatile functionality, making them a promising candidate in biomedicine. Natural medicines, including plants, animals, minerals, and their extracts, represent ideal precursors for CD synthesis due to their abundance, renewability, and eco-friendliness. This addresses sustainability and environmental concerns associated with conventional chemical precursors. Natural medicine-derived CDs (NM-CDs) feature quasi-spherical core-shell structures, ranging from 1 to 10 nm, with surface hydroxyl, carboxyl, and amino groups enhancing their hydrophilicity and functionality. Their properties can be further modulated by synthesis temperature and heteroatom doping. Critically, NM-CDs combine the pharmacological activities of natural medicines with the unique nanoscale properties of CDs, bridging traditional medicine and modern nanotechnology. This review provides a comprehensive overview of the development of NM-CDs, including green natural precursors, formation mechanisms, and synthesis strategies. It systematically analyzes the structure and properties of NM-CDs, categorizes their therapeutic applications into seven major disease types, and offers a detailed explanation of their fundamental pharmacological mechanisms. Finally, ten key opportunities and challenges for the sustainable development of NM-CDs are highlighted. By integrating efficient resource utilization, green chemistry principles, and clinical demands, NM-CDs exhibit strong potential to advance bio-based nanotherapeutics and enhance the value of natural medicines through modern scientific approaches.