Dynamic Excimer (DYNEX) Imaging of Lipid Droplets

This work was funded by grants CTQ2017-85658-R (MICIU/AEI/ERDF), FQM-337 (Junta de Andalucía), and PIUJA 2019-20 (Universidad de Jaén). We acknowledge the Universidad de Granada (Spain) microscopy central facilities (CIC-UGR) and computing time from CSIRC-UGR. M.C.G.-G. thanks MICIU/AEI for a predoctoral fellowship. Funding for open access charge: Universidad de Granada/CBUA. We are indebted to Prof. Reinhard Jahn for his generous support.Unraveling cellular physiological processes via luminescent probes that target specific cellular microenvironments is quite challenging due to the uneven distribution of probes. Herein, we designed a new dynamic excimer (DYNEX) imaging method that involves the sensitive detection of nanosecond-scale dynamic molecular contacts of a fluorescent acridone derivative and reveals the cell microenvironment polarity. Using our method, we specifically tracked cell lipid droplets in fibroblast colon carcinoma cells. These organelles play a central role in metabolic pathways, acting as energy reservoirs in regulatory processes. DYNEX imaging provides the inner polarity of cell lipid droplets, which can be related to lipid contents and metabolic dysfunctions. This new methodology will inspire development of novel multidimensional fluorescent sensors that are able to provide target-specific and orthogonal information at the nanosecond scale.CBUAMICIUUniversidad de GranadaUniversidad de JaénAgencia Estatal de InvestigaciónEuropean Regional Development Fund FQM-337Junta de Andalucía PIUJA 2019-2