Unveiling Cellular Secrets: Illuminating Carbon Dot Lighthouses for Improved Mitochondrial Exploration

Mitochondria play a significant role in cellular energetics and metabolism. Mitochondrial imaging is a powerful technique for monitoring dynamic changes within mitochondria and understanding the pathogenesis of various mitochondrion-associated diseases. The accidental discovery of carbon dots (CDs) in 2004 has opened new avenues for cellular bioimaging due to their remarkable photostability, biocompatibility, ease of synthesis, and significant fluorescence activity. Leveraging the unique physicochemical properties of stand-alone and ligand-attached CDs (CDS and CDL, respectively), they are actively being explored for targeted mitochondrial exploration. We review the diverse applications of CDS and CDL for mitochondrial exploration and underscore the pivotal role of mitochondria in cellular energetics and disease progression. Furthermore, we outline the evolution of CDs as mitochondria-targeting agents and underscore the importance of considering the subcellular distribution of CDs, a factor that is often overlooked. Herein, we discuss stand-alone CDs (CDS) and ligand-bound CDs (CDL) for targeting and imaging mitochondria in the initial sections. Further, we explore deeper in the mitochondria and discuss sensing of pH, ROS/RNS, sulfide, amino acid, viscosity, polarity, and ATP inside mitochondria. The last section covers mitochondria-targeted therapeutics. We aim to motivate the use of CDs for both imaging and therapeutic purposes, focusing on exploiting the potential of subcellular targeting using CDs.