Fluorescent small molecules

Fluorescent small molecules are used as dopants in either electron- or hole-transporting binders. These emitters are selected for their high photoluminescent quantum efficiency and for the color of their emission. Typical examples include perylene and its derivatives 44], quinacridones [45, penlaphenylcyclopenlcne [46], dicyanomethylene pyrans [47, 48], and rubrene [3(3, 49]. The emissive dopant is chosen to have a lower excited state energy than the host, such that if an exciton forms on a host molecule it will spontaneously transfer to the dopant. Relatively small concentrations of dopant are used, typically in the order of 1%, in order to avoid concentration quenching of their luminescence. 

Green fluorescent protein (GFP) and related fluorescent proteins can be used to label practically any protein or subcellular compartment of living cells (49). Transfection of cells with plasmids that encode appropriately targeted fluorescent fusion proteins has been used to define the plasma membrane, early endosomes, late endosomes, caveolae, the golgi complex, the ER, and other subcellular locations. Several fluorescent small molecules are also available for labehng specific cellular organelles, including endosomes and lysosomes, for analysis by fluorescence microscopy. 

Xue, S.,Yao, L., Shen, E, Gu, C., Wu, H., Ma,Y, 2012. Highly efficient and fully solution-processed white electroluminescence based on fluorescent small molecules and a polar conjugated polymer as the electron-injection material. Adv. Funct. Mater. 22,1092-1097. 

Myosin light chain phosphatase (MLCP) is an important protein in the regulation of cellular motility and division. We developed and synthesized a fluorescent small molecule (17e) that selectively inhibits MLCP. We found the growth of human prostate cancer cell lines with upregulated amounts of MLCP proves to be more sensitive when treated with our selective MLCP inhibitor. We used the fluorescent properties of 17e to image its entry and compartmentalization in human prostate cancer... 

Remember that I mentioned my PhD work involved the synthesis of fluorescent small molecules Fluorescent small molecules (Figure 8.2) are alternatives to fluorescent proteins for in vivo imaging. Some argue that small molecules, like fluorescein and rhodamine, offer advantages over proteins because they are much smaller than fluorescent proteins and therefore should cause less perturbation to the native biological system under investigation. 

A) Some fluorescent small molecules used for biological Imaging. 

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