Dynamic Excimer (DYNEX) Imaging of Lipid Droplets

Abstract

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.

Highly Efficient Red/NIR-Emissive Fluorescent Probe with Polarity-Sensitive Character for Visualizing Cellular Lipid Droplets and Determining Their Polarity

“…Notably, among the existing polarity-sensitive LD fluorescent probes, there are only very few ones (blue-emissive acridone, LDs-TPFP and C153, and green-emissive Lipi-DSB) that could be used to quantitatively determine the LD polarity. Moreover, their emission wavelengths are relative short and easily interfered by the cellular background fluorescence.…”

“…Furthermore, a few of LD fluorescent probes with environmental polarity-sensitive character have been developed very recently. − These fluorescent probes enable us to visualize LDs and to further reveal their polarity information. This is highly attractive for biological study of LDs, since the LD functions are closely related to their polarity.…”

“…Niu, Yu, and co-workers developed an excited-state intramolecular proton transfer-type fluorescent probe PPC for lambda scan real-color fluorescence imaging to study the hydrophobicity (polarity) of LDs . Garcia-Fernandez, Orte, and co-workers reported an idea of acridone excimers for fluorescence lifetime imaging to determine the LD polarity . Moreover, several polarity-sensitive LD fluorescent probes were proposed to be able to distinguish cancer cells from normal cells, − such as CTPA developed by Lin’ group, LD-TTP reported by Dong and co-workers, and LD-1 synthesized by Tang’s group .…”

Helically Chiral Hybrid Cyclodextrin Metal–Organic Framework Exhibiting Circularly Polarized Luminescence

“…The presence of such contributions is related to the existence of dynamic PyC – –PyC – interactions within the time frame of the excited state. The detection of localized dynamic excimers in FLIM imaging has been accounted for only recently and constitutes a novel image-filtering tool called DYNEX. Applying the DYNEX criterion to images of the PyC – ⊂CD-HF in MeOH reveals (Figure S28c) the specific points where actual dynamic excimer formation is detected.…”

Solvatochromic Two-Photon Fluorescent Probe Enables In Situ Lipid Droplet Multidynamics Tracking for Nonalcoholic Fatty Liver and Inflammation Diagnoses

“…Lipid droplets are dynamic organelles whose motor behaviors are closely related to cell metabolism. , To further examine the capability of lip-YB in the monitoring of lipid droplet dynamics, herein, lip-YB was coincubated with HepG2 cells treated by oleic acid. As depicted in Figure S18, lipid droplets in the observed area moved distinctly in the period of 120 s, and four different pseudocolors were adopted to demonstrate the movements at various time nodes (0, 40, 80, and 120 s).…”