Prof. Dr. Axel Müller

Complexes were formed via the electrostatic interaction between 50-nm anionic liposomes and a star-shaped polyelectrolyte having cationic arms that radiate from a silicon-based central core. The complexation was investigated with attention given to assessing the capacity of the cationic stars for the anionic liposomes (both liquid and solid); the integrity of the complexed liposomes; and the stability of the resulting star/liposome complexes in aqueous salt solutions. We have found that by changing the content of anionic groups in the liposomal membrane as well as the phase-state of membrane, the stability of star/liposome complexes in aqueous salt media can be controlled. The liquid liposomes with 0.1 mole fraction of anionic phosphatidylserine (PS^1-), and solid liposomes with 0.1 mole fraction of PS^1-, retain their integrity when bound to the stars, with the resulting star/liposome complexes being stable in a physiological solutions, e.g. [NaCl] = 0.15 M. Multi-liposomal complexes, containing up to 10 liposomes per star, seem to hold promise as carriers for biologically active compounds.