Super-Resolution Microscopic Imaging of Lipid Droplets in Living Cells via Carbonized Polymer Dot-Based Polarity-Responsive Nanoprobe.

Lipid droplets (LDs) are dynamic subcellular organelles that participate in various physiological processes, and their abnormality can also lead to various diseases. Tracing the dynamics of LDs in living cells will be valuable for understanding cell physiological states. Here, we employed a structured light illumination super-resolution imaging assisted with a carbonized polymer dot (CPD)-based fluorescence nanoprobe to track the travel paths of LDs and other organelles. The CPDs we developed are highly biocompatible with living cells and exhibit a highly sensitive response to solvent polarity, allowing for high specificity in staining LDs in living cells. Aided by these nanoprobes, we successfully observed many real-time LD-involved dynamics in living cells, such as intracellular LD interactions, communications with other organelles, and dynamic behaviors under external stimuli (oxidative stress inducer). These studies deepen our comprehension of the physiological role of LDs and drive the advancement of super-resolution fluorescent probes.