An analytical nanoplatform based on carbon dots for real-time mitochondrial imaging and simultaneous reactive oxygen species modulation in live cells

Real-time monitoring of mitochondrial dynamics is critical for understanding associated diseases, yet existing analytical methods relying on conventional organic fluorophores suffer from high background interference and signal distortion in complex biological matrices. Furthermore, fluorescent analytical methodologies capable of high-fidelity in situ mapping and simultaneous active microenvironment intervention remain scarce. Herein, we report an advanced dual-functional analytical nanoplatform based on engineered carbon quantum dots (Mito-H₂O₂-CDs) that overcomes these limitations by integrating highly specific electrostatic anchoring with surface boronic acid-mediated reactive oxygen species (ROS) responsiveness. Analytically, this methodology relies on robust non-covalent electrostatic interactions to achieve exceptional targeting specificity (Pearson correlation coefficient of 0.89), which strategically eliminates the necessity for cell-stress-inducing washing steps and ensures wash-free, ultra-low background quantitative imaging in live cells. Beyond providing high-spatiotemporal-resolution analytical tracking of mitochondrial dynamics in situ, the probe functions as an active analytical tool. Standard quantitative assays demonstrated its sensitive fluorescence response and exceptional capacity to specifically scavenge excessive H₂O₂ in vitro (reaching 91.6% efficiency) via surface chemical reactions. This dual functionality prevents analytical artifacts caused by oxidative framework dissociation and delays mitochondrial morphological collapse in living cells. Consequently, this work advances the field of analytical chemistry by providing a reliable, interference-free analytical strategy for long-term mapping of subcellular environments under active oxidative stress intervention.