Amphiphilic Carbon Dots for Ultrafast and Wash-Free Mitochondria-Targeted Imaging.

Abstract

Carbon dots (CDs) exhibit exceptional biocompatibility and programmable amphiphilicity, establishing them as transformative nanomaterials for subcellular visualization with exceptional resolution. However, existing CD-based probes lack the spatiotemporal precision required for real-time organelle tracking, particularly in mitochondrial-targeted imaging via ultrafast, wash-free protocols. To overcome these limitations, this study describes the solvent-free, high-temperature (280 °C) and short-time (2 h) preparation of green-emitting CDs (GCDs) with distinctive amphiphilic architectures utilizing benzoylurea and citric acid in a sealed high-pressure reactor. GCDs may form micelle-like structures driven to hydrophobic interactions, producing long-wavelength emission in contrast to blue emission in low-polar solvents. They also simultaneously activate the synergy of numerous endocytotic modes, achieving ultrafast (<5 s) and wash-free imaging. GCDs can also effectively target the mitochondria, more significantly, in both normal and cancer cells (Person's value ≈ 0.90/0.91), which is explained by the minor adjustment of mitochondrial membrane potential. This work describes assembly mechanisms of amphiphilic CDs while establishing potential design principles for mitochondria-targeted nanostructures with wash-free, ultrafast tracking.