Surface‐Engineered Carbon Dots for Monitoring of Lysosomal Viscosity and Organelle Dysfunction

ABSTRACT

The development of robust, photostable nanoprobes for precise organelle targeting remains a cornerstone in chemosensing and advanced bioimaging. Alterations in the lysosomal microenvironment serve as an indicator of organelle health and disease progression. Herein, a sustainable synthetic strategy is presented for benzothiazole‐modified carbon dots (LysoDots), engineered for specific lysosome localization and viscosity monitoring. LysoDots display a viscosity‐dependent fluorescence enhancement in glycerol‐water systems while remaining insensitive to physiological pH and temperature variations. This turn‐on response allows for the high‐fidelity tracking of lysosomal microviscosity changes induced by exogenous stimuli, such as nystatin, and endogenous processes like rapamycin‐induced autophagy. Confocal imaging demonstrates a remarkable colocalization of LysoDots with the commercial lysosome marker, LysoTracker Green (LTG), showing a Pearson's correlation coefficient of 0.92 in CAL‐33 oral carcinoma cells, with the red emission effectively differentiating lysosomal viscosity profiles between cancerous and non‐cancerous cells. Furthermore, the LysoDots were successfully employed in a neuronal model, SH‐SY5Y cells, where the probe effectively tracked glutamate‐induced lysosomal dysfunction, mimicking the pathology of lysosomal storage disorders, along with the viscosity restoration mediated by trehalose. These findings highlight the potential of LysoDots as a biocompatible, photostable, multi‐functional nanomaterial for long‐term monitoring of lysosomal dynamics and cellular homeostasis.