Small-molecule fluorophore

It should also be noted that comparison of quenching efficiency of conjugated polymers with small-molecule fluorophores is complicated and oversimplification can lead to misleading claims of exceptional sensitivity enhancements. In their 2007 review, Swager and co-workers discuss cases where the charge state of the small molecule used for comparison differed fundamentally from the polymer and exceptional quenching efficiencies were inappropriately attributed to super-quenching alone [3], In addition, a polymer will create a different local... 

Fig. 8 Comparison of quenching of small-molecule fluorophores vs. conjugated polymers...

Recently, a small molecule fluorophore phosphosensor technology referred as Pro-Q Diamond dye has been developed to detect and quantitate phosphorylated amino acids within peptides and proteins in microarrays. ° In addition to binding assays, fluorescence detection methods have also been developed for functional assays. For example, microarrays of quenched fluorescent substrates can be used to detect protease or esterase activities in the analytes. In this method, quenched fluorescent substrates are prepared by coupling the peptide substrate to coumarin, a fluorescent dye. These peptide substrates are then spotted onto the solid support... 

Morales AR, Yanez CO, Zhang Y, Wang X, Biswas S, Urakami T, Komatsu M, Belfield KD (2012) Small molecule fluorophore and copolymer RGD peptide conjugates for ex vivo two photon-fluorescence tumor vasculature imaging. Biomaterials 33 8477-8485... 

Carrocci, T. J. Hoskins, A. A. Imaging of RNAs in live cells with spectrally diverse small molecule fluorophores. Analyst 2014,139,44 7. 

Rozinov, M. N. Nolan, G. P. Evolution of peptides that modulate the spectral qualities of bound, small-molecule fluorophores. Chem. Biol. 1998, 5, 713-728. 

Figure 8.2. (A) Some examples of small-molecule fluorophores used for biology and cellular imaging studies. These fluorophores can be modified synthetically to provide fluorescent molecules with properties like biological analyte sensing capabilities. (B) Chemical reaction that affords an esterified version of fluorescein and subsequent hydrolysis of the ester linkages by intracellular esterases following entry into the cytoplasm.

If you look in the Molecular Probes catalog, you ll see that a number of small-molecule fluorophores are sold as organelle markers. For instance, MitoTracker Red is sequestered by the mitochondria and LysoTracker Green localizes to the lysosomes. Hoescht is a stain that is specific for cell nuclei. It provides a way to study nuclear morphology, which is an indicator of cell health. For instance, unhealthy and dying cells exhibit condensed nuclei, whereas healthy cells have nuclei that are somewhat oval shaped. 

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