Live cell imaging of lipid droplets: fluorescent chalcones as probes for lipophagy and lipid-mitochondria interactions.

Lipid droplets are crucial organelles involved in cellular energy storage and metabolism, which is key in maintaining energy homeostasis through lipophagy. In this work, we successfully synthesized donor-acceptor chalcone derivatives (M1-M3) with improved photophysical characteristics, such as significant Stokes shifts and strong emission features. DFT and TDDFT calculations have been employed to evaluate the structure-property relationship of the chalcone derivatives.

Diphenylbutadiene Fluorescent Analogues in Sub-Cellular Imaging and Monitoring Mitophagy.

A series of donor-acceptor (D-π-A) substituted diphenylbutadienes exhibiting solvatochromic emission and a large Stokes shift (100-200 nm) were designed and synthesized for distinctive organelle labelling, enabling real-time monitoring of organelle behaviour such as lysosomal dynamics, mitophagy monitoring, and stress responses. The morpholine-substituted D-A-D diphenylbutadiene (M2) was employed to investigate selective imaging of lysosomes, the uptake of damaged mitochondria through mitophagy, and monitoring lysosomal viscosity or pH changes. Other diphenylbutadiene derivatives (M1, M3, M4) selectively accumulated in lipid droplets.

Substitution Effects on Subcellular Organelle Localization in Live-cell Imaging.

A series of D-π-A indole-containing fluorescent probes were developed, followed by an investigation of their photophysical properties and compounds' suitability for subcellular imaging in living cells. We demonstrate that the preference for mitochondrial localization was lost when morpholine was substituted, resulting in the accumulation of the molecule in the lysosomes. However, interestingly, the presence of a nitro group led to their localization within the lipid droplets despite the presence of the morpholine pendant.

Fluorescent styrenes for mitochondrial imaging and viscosity sensing.

Fluorophores bearing cationic pendants, such as the pyridinium group, tend to preferentially accumulate in mitochondria, whereas those with pentafluorophenyl groups display a distinct affinity for the endoplasmic reticulum. In this study, we designed fluorophores incorporating pyridinium and pentafluorophenyl pendants and examined their impact on sub-cellular localization. Remarkably, the fluorophores exhibited a notable propensity for the mitochondrial membrane.

-Functionalized fluorophores: detecting urinary albumin and imaging lipid droplets.

A series of novel -sulfonyl pyridinium fluorophores were designed, synthesized, and explored in terms of their ability to bind with serum albumins. Upon binding the fluorophores with BSA, noticeable emission wavelength or intensity changes accompanied by color changes were observed. Competitive binding studies revealed that the fluorophore selectively binds to the warfarin site, but the binding affinity also depends on the nature of the scaffold.