Bioimaging and therapeutic applications of multifunctional carbon quantum dots: Recent progress and challenges

Carbon quantum dots (CQDs) have emerged as highly promising carbon-based nanomaterials in the field of nanomedicine. Their small size and unique physicochemical properties such as biocompatibility, tunable surface functionalities (such as amino, hydroxyl, carboxyl), stability and electron mobility, make them particularly advantageous for biomedical applications. CQDs show great potential as nanocarriers for drug delivery in the treatment of cancer, ophthalmic diseases, infectious diseases, cardiovascular diseases and neurological disorders. Additionally, their versatility has prompted growing interest in utilizing CQDs for gene therapy, vaccine development, stem cell therapy and tissue engineering. CQDs have also advanced bioimaging and biosensing due to their excellent optical properties, including high fluorescence, tunable emission, and photostability, making them ideal for in vivo imaging, cellular tracking, and biomolecule detection. Despite these promising applications, limitations such as non-biodegradability, potential cytotoxicity at higher concentrations, and inconsistent surface functionalization pose challenges to their efficacy and safety in biomedical applications. This review highlights recent advancements in the therapeutic use of CQDs, underscoring their potential to transform nanomedicine by offering precise and targeted drug delivery. In the future, CQD-based systems could facilitate more effective therapies with reduced off-target effects, paving the way for a new era of precision medicine.