A dual-fluorophore sensor approach for ratiometric fluorescence imaging of potassium in living cells

We report a dual-fluorophore approach for ratiometric fluorescent imaging of K+ levels in live cells. Intracellular esterases cleave RPS-1 to detach the K+-responsive fluorophore (PS525) from its internal standard (Coumarin 343).

Förster resonance energy transfer in fluorophore labeled poly(2-ethyl-2-oxazoline)s

A well-defined FRET system based on heterotelechelic poly(2-ethyl-2-oxazoline) containing pyrene and coumarin 343 was successfully used as fluorescent probe for temperature sensing and processed into fibres and films showing excellent FRET efficiency.

Cholic acid dimers as invertible amphiphilic pockets: synthesis, molecular modeling, and inclusion studies

Two dimers of cholic acid were synthesized through simple covalent linkers. The dimers form invertible molecular pockets in media of different polarity; hydrophobic pockets are formed in water and hydrophilic pockets are formed in organic media. Fluorescence studies show that pockets formed by these dimers can serve as invertible hosts for the hydrophobic guest pyrene and the hydrophilic guest coumarin 343. The molecular pocket also enhances dissolution of the weakly soluble cresol red sodium salt in organic media. Molecular modeling was performed to better understand the host–guest complexation process of the invertible amphiphilic pockets. The calculated free energy changes indicate that the two dimers form the most stable complexes with coumarin 343 at a host to guest ratio of 2:2, whereas the host to guest ratio differs in the formation of complexes with pyrene for the two dimers. The dimer with the shorter, less flexible linker seems to form host–guest complexes that are more stable in both water and organic solvents.