Membrane permeability chromophores

Finally, the effect of different chemosensitizers on the permeability of liposomes loaded with the membrane-impermeable chromophore carboxyfluorescein (CF) was studied as a model for the assumed change in membrane permeability of a number... 

Membrane characteristics, such as membrane potential and ion permeability, can be controlled by photoirradiation when photoisomerizable chromophores are incorporated into the membrane. The membrane can fabricate an organic-photosensor, which changes the potential in an on-off fashion when light irradiation is used as an input signal. Such an application of organic membranes is of considerable interest in connection with the development of molecular based electronic devices. 

Determination of the diffusion coefficient by permeability experiments [42], when a liquid membrane is clammed between a feed and receiving phase, with a membrane solvent. At time t = 0, a carrier which is substituted with a chromophoric group is added to the feed phase ([cf]o). The carrier diffuses through the membrane and the increase of concentration in the receiving phase ([cj() is monitored by UV/Vis spectroscopy (dj as a function of time. The transport through the pores of the membrane is assumed to be rate limiting and Eq. (25) is derived ... 

Artificial membranes are a relatively low-cost assay for fast screening of transcellular passive diffusion. The system allows easy access to permeability pH profiles and unstirred water layer correction. Due to the simple composition of the buffer reagents, the analytics is much easier than with cell cultures. Straight UV detection can be used in most cases and LC-MS (low soluble samples or compounds lacking UV chromophore) is considerably simplified in comparison to Caco-2, as the system matrix is relatively simple. A reasonable correlation has been obtained between artificial membrane and reported human GIT permeability in our laboratory (Figure 15.6A). 

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