Interactions of functionalized vesicles in the presence of Europium (III) chloride [Elektronische Ressource] / von Christopher K. Haluska

Max Planck Institüt für Kolloid- und Grenzflächenforschung Arbeitsgruppe Prof. Dr. Reinhard Lipowsky Interactions of Functionalized Vesicles in the Presence of Europium (III) Chloride Dissertation zur Erlangung des akademischen Grades "doctor rerum naturalium" (Dr. rer. nat.) in der Wissenschaftsdisziplin Experimentelle Physik eingereicht an der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam von Christopher K. Haluska Potsdam im Oktober 2004 - 2 - Abstract We incorporate amphiphilic receptors bearing ß-diketone functional units intolarge (LUV’s) and giant unilamellar vesicles (GUV’s). Electrolyte solutions containing di- and trivalent ions were used to induce inter-membrane interactions. Measurements performed with isothermal titration calorimetry (ITC) revealed that interaction between EuCl and ß-diketone receptors was characterized by a molar 3-1enthalpy 126 ± 5 kcal/mole and an equilibrium binding constant 26 ± 4 mM . The results indicate a molecular complex formed binding two ß-diketone receptors to one 3+Eu ion. Dynamic light scattering (DLS) was used to follow changes in LUV diameter indicated in an increase in vesicle size distribution of on average 20 %. Optical microscopy was employed to visualize the inter-membrane interaction measured using DLS and ITC.