Perylene membranes

Margineanu, A., Hotta, J., Auweraer, M. V. D., Ameloot, M., Stefan, A., Beijonne, D., Engleborghs, Y., et al. 2007. Visuahzation of membrane rafts using a perylene monoimide derivative and fluorescence hfetime imaging. Biophys. J. 93 2877-91. 

The term exdmer is used when the excited dye forms a transient fluorescent dimeric complex with another fluorophore of the same kind. The exdmer fluorescence is usually red shifted with respect to that of the monomer (see Fig. 6.28) The most widely used types of eocdmer-forming probes are pyrene (see Fig. 6.28) and perylene and their derivatives. The ratio of the maxima of the excimer to the monomer spectra can be used to judge the efficiency of exdmer formation. This (Ex/Mo)-ratio depends on the concentration of the dye and is controlled by the diffusion properties. It allows, when using pyrene or perylene labeled fatty acids or phospholipids (see Fig. 6.28), the estimation of the probe s lateral diffusion coefficients in lipid bilayer membranes. Thus, membrane fluidity can be measured by monitoring the fluorescence spectra of such an exdmer probe. 

Since the early studies of membranes labeled with fluorescent probes, there has been an extensive effort to determine the location of the probes in the memtx es. Early membrane probes, such as perylene, 9-vinylanthrac e, and were simple hydrophobic molecules that dissolved in the hydrophobic regions of micelles or mem-Ixmies. SubsequOTt probes woe synthesized and designed to localize the fluorophoie at various depths in the membrane. Among the earliest of such probes were theandiroyl-... 

In the recent past liquid membranes were employed for the separation and extraction of materials, and they can be conveniently employed for separating biological materials [129-137], Microemulsions of Winsor I (o/w) and Winsor II (w/o) types are considered dispersed liquid membranes that can augment the transfer of oil-soluble and water-soluble compounds, respectively, across them by trapping them in microdroplets for convenient uptake and subsequent release. The microemulsions (Winsor I and II) are called bulk liquid membranes. They are recent additions in the field of separation science and technology. This field has been fundamentally explored and advanced by Tondre and coworkers [138-147], who worked out the fundamentals of the transport process by studying the transfer of alkali metal picrates and other compounds across the w/o microemulsions [140-142], They also studied the transport of lipophilic compounds (pyrene, perylene, and anthracene) across o/w liquid membranes [138,139],... 

Figure 3 Migration of the solvent fronts and substances during continuous development using OPLC technique (26), Chromatographic conditions CHROMPRES 25 (Labor MIM, Budapest, Hungary) silica gel 60 (Merck) isooctane-THF (100 7.5,v/v) external pressure on the membrane, 2.0 MPa. L, migration distance S, start point I, eluent inlet point 0, eluent outlet point. 1, a front (Fa) 2, front of total wetness (Fm>) 3, P front (Fp) 4, inlet pressure (Pe) 5, curve of eluent volume at outlet (Vf) 6-10, substances separated (6, blue dye, eluting in Fp 7, perylene 8, yellow dye 9, pink dye 10, red dye). Stages of continuous development 1, classical, fully off-line OPLC II, leaving of partially wetted zone III, leaving of secondary fronts IV, equilibration.

Keywords Hydrophobic interactions Membranes Perylene diimides Self-assembly - water... 

Different types of mimetic systems of biological membranes including vesicles (spherical phospholipid bilayers), LB monolayers, hybrid bilayers (HBLs) and tethered lipid bilayers were used in SERS investigations. LB films are monomolecular films that can be fabricated from amphiphiles at the water-air interface and transferred to a SERS solid substrate (such as island film). For SERS studies, the target molecule was treated as a dopant in a monolayer matrix formed for example by arachidic acid or phospholipids. Aroca and co-workers applied the LB technique to detect SERRS signal firom a variety of chromophores such as several perylene derivatives and RH6G even in SM level in some cases (Aroca 2006). HBLs are monolayers of phospholipids incorporated into SAM of long-chain thiols such as... 

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