ANYL 62 |
| Design of fluorescent microscopes and selection of dyes is better served by the knowledge of surface affects on dyes whether it is in vitro or in vivo. Environmental influences on dye properties have been known for long time. Solvent properties, e.g. hydrophilicity, buffer composition, etc. can affect both quantum efficiency as well as absorption and emission spectra. The change in former can be very substantial. A dye can be totally non-fluorescent in aqueous buffers, but highly fluorescent in organic solvents or lipid environments. Attachment of dyes to macromolecules also has significant effects on dye properties. Not only it changes fluorescence polarization and life times, as expected, it can also affect the fluorescence intensity as well as absorption and emission spectra. In fact we have observed that attachment of dyes to macromolecules can increase or decrease Stock shift, which can be very useful for many applications. Finally another observation we made recently is the changes in spectra when these dyes are immobilized on solid surfaces such as glass slides or tissue samples. These changes can be very dramatic or insignificant depending on the dye, substrate type and attachment chemistry (i.e. linkers). The absorption and emission spectra were measured for H&E stained tissue samples as well as for cell cultures labeled with eGFP and Cy-dyes. Red spectral shift values varied from few nanometers to more than 50 nanometers. Taking into account spectral shifts improves the efficiency and image quality of full-field and confocal microscopy and should be carefully considered by scientists conducting biological sample studies. |
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General Posters
7:00 PM-9:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Analytical Chemistry |