Molecular Probes for Fluorescence Lifetime Imaging

Abstract

Visualization of biological processes and pathologic conditions at the cellular and tissue levels largely rely on the use of fluorescence intensity signals from fluorophores or their bioconjugates. To overcome the concentration dependency of intensity measurements, evaluate subtle molecular interactions, and determine biochemical status of intracellular or extracellular microenvironments, fluorescence lifetime (FLT) imaging has emerged as a reliable imaging method complementary to intensity measurements. Driven by a wide variety of dyes exhibiting stable or environment-responsive FLTs, information multiplexing can be readily accomplished without the need for ratiometric spectral imaging. With knowledge of the fluorescent states of the molecules, it is entirely possible to predict the functional status of biomolecules or microevironment of cells. Whereas the use of FLT spectroscopy and microscopy in biological studies is now well established, in vivo imaging of biological processes based on FLT imaging techniques is still evolving. This review summarizes recent advances in the application of the FLT of molecular probes for imaging cells and small animal models of human diseases. It also highlights some challenges that continue to limit the full realization of the potential of using FLT molecular probes to address diverse biological problems, and outlines areas of potential high impact in the future.

Use of Fluorescence Lifetime Imaging Microscopy (FLIM) as a Timer of Cell Cycle S Phase

“…In contrast, fluorescence lifetime, being a structural and environmental signature of a fluorophore dye [13, 14], is largely independent on the above interfering factors. Fluorescence Lifetime Imaging Microscopy (FLIM) allows discrimination of fluorophors with different structures, lifetime characteristics and microenvironment, and is well-suited for quantitative, multi-parametric imaging of complex biological specimens [15].…”

Cellulolytic RoboLector – towards an automated high-throughput screening platform for recombinant cellulase expression

“…It must be considered, that fluorescence measurement depends on many factors such as pH and ion concentrations [31]. After the extraction from the protecting cells, the FbFP was exposed to the respective environment.…”

Fluorescent mesomorphic pyrazinacenes

“…We have also observed (as have others in similar compounds 29 ) the variation of electronic absorption and emission wavelengths depending on local acidity in these compounds and we are currently studying this feature with a few to develop pH indicators for use in non-polar solvents. 49 These compounds are worthy targets for use in fluorescence lifetime imaging applications 36 and we will report our efforts in that direction later. …”

“…The excellent quantum yields of the compounds make their derivatives suitable for fluorescence lifetime imaging as has been reported for other fluorescent compounds. 36 Thermotropic properties X-ray powder diffraction studies of the compounds reveal several different mesophases with molecular structure partly indicating the resulting morphologies. Notably, all compounds except 8 and 9 melt to an isotropic state without undergoing phase transitions.…”