Nile red

Doubly doped polymers can be used to enhance two functions. For example, Wu et al. [58] added Alq3 as an election transport agent and nile red as an emitter to hole transporting PVK. 

It has been reported that while in aqueous solution the lifetime of optically excited nile red is 0,65 ns inside AOT-reversed micelles it is 3,73 ns, becoming 2,06 ns at/ = 30 [150],... 

Host-guest systems made from dendritic materials have potential in the areas of membrane transport and drug delivery [68, 84, 85]. In a recent report [136] Tomalia and coworkers investigated structural aspects of a series of PAM AM bolaamphiphiles (e.g., 50) with a hydrophobic diamino do decane core unit. Fluorescence emission of added dye (nile red) was significantly enhanced in an aqueous medium in the presence of 50 unlike the cases when 51 and 52 were added (Fig. 23). Addition of anion surfactants to this mixture generated supramolecular assemblies which enhanced their ability (ca.by 10-fold) to accommodate nile red (53). Further increase in emission was noted by decreasing the pH from the normal value of 11 for PAMAM dendrimers to 7. At lower pH values the... 

Sarkar N, Das K, Nath DN, Bhattacharyya K (1994) Twisted charge transfer processes of Nile red in homogeneous solutions and in faujasite zeolite. Langmuir 10(l) 326-329... 

Hazra P, Chakrabarty D, Chakraborty A, Sarkar N (2004) Intramolecular charge transfer and solvation dynamics of Nile red in the nanocavity of cyclodextrins. Chem Phys Lett 388(1-3) 150-157... 

Jee AY, Park S, Kwon H, Lee M (2009) Excited state dynamics of Nile red in polymers. Chem Phys Lett 477(1-3) 112-115... 

Cser A, Nagy K, Biczok L (2002) Fluorescence lifetime of Nile red as a probe for the hydrogen bonding strength with its microenvironment. Chem Phys Lett 360(5-6) 473-478... 

Fig. 6.8. Structures of some common fluorophores. DPH = diphenylhexatriene NBD = nitrobenzoxadiazole Tb-DTPA-csl24 = terbium diethylenetriaminepentacetate-carbostyril 124, DAPI = 4, 6-diamidino-2-phenylindole Nile red = 9-(diethylamino)-5H-benzo-[a]phenoxazin-5-one.

Many fluorophores are sensitive to changes in the hydropho-bicity of the immediate environment. Therefore, bringing these fluorophores into a different environment may also produce a change in FRET, when a second fluorophore is affected by the emission change of the first. Fluorophores like Nile Red with changes of up to 100 nm when transferred from water to an aprotic organic solvent are principally suitable for such an approach [71], Molecular rotors have the characteristic of having a quantum yield that depends on the viscosity. Such dyes are formed by an electron donor unit and an electron acceptor unit that can rotate relative to each other upon photoexcitation with a behavior that depends on the viscosity of the environment. These dyes have been included in FRET probes for viscosity studies [53],... 

Sackett, D. L. and Wolff, J. (1987). Nile red as a polarity-sensitive fluorescent-probe of hydrophobic protein surfaces. Anal. Biochem. 167, 228-234. 

Brown, M., Edmonds, T., Miller, J. and Seare, N. (1993). Use of nile red as a long-wavelength fluorophore in dual-probe studies of ligand-protein interactions. J. Fluorescence 3, 129-130. 

An important demonstrated application of this artificial nose system is the high-speed detection of low levels of explosives and explosive-like vapors. Several sensors, based on Nile Red attached to silica microspheres, show high sensitivity to nitroaromatic compounds (NAC) within a mixture12. Different fluorescence response profiles were observed for several NAC s, such as 1,3,5-trinitrotoluene (TNT) and 1,3-dinitrobenzene (DNB), despite their similar structures. These responses were monitored at low concentrations of the NAC vapors (ca. 5 ppb) and at short vapor exposure... 

Figure 8. Seventy-six sensor beads (Jupiter C4/Nile Red) monitored to show that the average responses for three consecutive 0.38-s exposures of 50% saturated vapor levels result in reproducible and high-speed response profiles. The sensors are positioned on the distal tip of an optical imaging fiber and relative analyte concentrations are 0.5 and 18700 ppm for 1,3-DNB and toluene, respectively. Reprinted with permission from ref 12a. Copyright 2000 American Chemical Society.

Fig. 10 (a) Chemical structure of PEG-6-PCL copolymer, (b) CLSM image of PEG-6-PCL polymersomes containing membrane-encapsulated Nile Red (2 mol%) and aqueous entrapped Calcein dyes. Scale bar 5 pm. (c) Cryo-TEM image of PEG-6-PCL polymersomes. Scale bar 100 nm. Reprinted from [228] with permission... 

The simplest method yet most complex structure for white OLEDs consists of three primary emission colors blue, green, and red. Kido et al. reported using three emitter layers with different carrier transport properties to produce a white emission [273], The multilayer structure of such an OLED is ITO/TPD/p-EtTAZ/Alq3/Alq3 Nile Red/Alq3/Mg Ag, in which a blue emission from the TPD layer, a green emission from the Alq3 layer, and a red... 

Fluorescence Examples Nile Red 0.7 (dioxane) Cy3 0.04 (phosphate buffer) Alexa 0.12 (phosphate buffer) IR125 0.04 (MeOH) 1-10 ns, monoexponential decay CdSe 0.65-0.85 CdTe 0.3-0.75 PbSe 0.12-0.81 CuInS2 0.2-0.3 10-100 ns, typically... 

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