"The major goal of the proposed project is to facilitate the applicant’s reintegration to his home institute after a successful Marie Curie training period at the Surface Chemistry, Dept. of Chemistry, KTH, Stockholm. To reach this goal the host (Eötvös Lorand University, Budapest) offers a permanent position for him and provides the infrastructure necessary to implement the proposed research project. The proposed research project consists of two independent work packages. The first work package aims at developing and applying a nanoprobe technique to determine the optimal structure of DNA-polyelectrolyte complexes, which is an important step required to increase the efficiency of current non-viral gene delivery systems. The second work package will map the effect of multivalent ions on the interaction of a flexible polyelectrolyte and an oppositely charged surfactant, which will provide information how the strong ion-ion correlations, introduced by the multivalent ions, affect surfactant/polyelectrolyte self-assembly. Finally, the reintegration grant will allow the researcher to transfer his new competences (related to modern surface characterization techniques, e.g. DPI, AFM, QCM-D, ellipsometry) to the host institution of the reintegration period and to the wider audience of its students."