Carbon Dots for Nucleic Acid-Based Diagnostics and Therapeutics: Focus on Oxidative DNA Damage

Carbon dots (CDs) are gaining significant attention as multifunctional nanomaterials due to their optical properties, aqueous dispersibility, redox activity, and overall biocompatibility. This review presents a critical overview of the recent advances concerning the application of CDs in nucleic acid-centered diagnostics, with a specific focus on oxidative DNA damage. The use of CDs for the detection of oxidative DNA damage biomarkers, such as 8-oxo-2 '-deoxyguanosine (8-oxo-dG), and their potential roles as fluorescent probes in environments related to oxidative stress is discussed in detail. The relationship between surface functionalization and biological performance is examined, highlighting how physicochemical properties dictate both the beneficial and adverse biological responses to CDs. Remarkably, CDs can act as antioxidants, mitigating oxidative damage, or as pro-oxidants, inducing cytotoxic effects, an ambivalent behavior that can be strategically harnessed for cytoprotection or selective tumor cell killing. Overall, this review outlines how CDs can contribute to the development of precision tools for studying oxidative environments affecting nucleic acids, with important implications for both diagnostics and redox-based therapeutic strategies of human diseases.