Membranes lanthanide ions

Lanthanide ions also affect the conformation of the artificial membranes as reflected in the increase in width [128] of the bilayer by 6 A and the polar head groups are oriented... 

Affinities of lanthanide ions for phosphatidylcholine bilayer membranes. 

Kamen DE, Cahill SM, Girvin ME. Multiple alignment of membrane proteins for measuring residual dipolar couplings using 60. lanthanide ions bound to a small metal chelator. J. Am. Chem. 

Supported liquid membranes, consisting of an organic solution of -octyl(phenyl)-A,iV-diisobutylcarbamoylmethylpho-sphine oxide (CMPO) and tributyl-phosphate (TBP) in decalin, were capable of selective separation and concentration of actinide and lanthanide ions from aqueous nitrate feed solutions and from synthetic nuclear wastes where the strip solution is a mixture of formic acid (FA) and hydroxylammonium formate (HAF) [106,107]. TBP is added to CMPO to improve its solubility in aliphatic diluents. Although low concentration of nitric acid was initially used as the strippant solution, a gradual... 

Almost no report is available on the membrane transport studies of trivalent actinide ions with macrocyclic carriers. However, there are some literatures available on trivalent lanthanide ions, which can be used as guidelines for any future studies. Brown et al. [143] and Zhu and Izatt [144] have used bis(l-hydroxyUieptyl)DC18C6 as the membrane carrier and... 

Sugiura, M., Transport of lanthanide ions through cellulose triacetate membranes containing hinokitiol and flavonol as carriers. Sep. Sci. Tech., 1990, 25 1189-1199. 

Ma C, Opella SJ (2000) Lanthanide ions bind specifically to an added EF-hand and orient a membrane protein in micelles for solution NMR spectroscopy. J Magn Reson 146 381-384... 

Sugiura, M. 1993. Effect of quaternary ammonium-salts on carrier-mediated transport of lanthanide ions through cellulose triacetate membranes. Separation Science and Technology 28 1453-1463. 

A carrier molecule can have structure or binding sites that make it suitable to transport a specific ion or class of ions. Valinomycin, for example, binds univalent K+ ion to initiate the four-step carrier/ion cycle. A class of macro-cyclic molecules, the crown ethers, absorbs ions into the central cavity of their crown-like structure to produce the membrane-soluble ion complexes. Special ionophores like lasalocid and A23187 with judiciously placed carboxyl groups are selective for polyvalent ions such as Ca (II) or lanthanide ions like Eu (III). The ionophore wraps around the ion as the carboxyl groups bind to produce the membrane soluble complex ion. 

ABO3 perovskite-type oxides with transition-metal ions at the B-site have high ionic and electronic transport in the form of p or n semi-conductivity (mixed ionic and electronic conductivity), caused by different oxidation states of the transition-metal cation. For dense ceramic membranes, perovskite-type oxides with the following cations are preferred A = Ln (lanthanide ion), Ca, Sr, Ba B = Cr, Mn, Fe, Co, Ni, Cu. 

Moreno, C Valiente, M. Studies on the mechanism of transport of lanthanide ions through supported liquid membranes containing di-(2-ethylhexyl) phosphoric acid (DEHPA) as a carrier. Journal of Membrane Science, 1999, 155, 155-162. 

In parallel, other lanthanide ions have also been used in these experiments, in particular, the [Lu2(L )3] complexes with Ln = Eu°, Tb , and, to a lesser extent Sm (with overall quantum yields in water at pH 7.4 of 21%, 11%, 0.38%, and lifetimes amounting to 2.43 ms, 0.65 ms, and 30.4 p,s, respectively). It is possible to perform time-resolved microscopy with these different probes. They have specific spectral signatures, and the discrimination can be done as a fimction of the luminescence intensity as well as a fimction of the lifetime decay of the excited states. A proof of concept has been performed with HeLa cells and is presented in Figure 17. The present probes are localized within the same cell compartment. However, once being addressed to different compartments or different targets (such as receptor at the surface of cell membrane) a specific detection can be envisaged. This concept will be illustrated below. 

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