none5This paper describes the synthesis and the physico-chemical characterisation of cationic peptides (CPs) for possible application as non-viral gene delivery systems. Particularly, the production of cationic liposomes and micelle solutions was considered. Five CPs, namely tetralysine cholesteryl hemisuccinate, tetralysine palmitate, tetralysine 3,7-diacetyl-ursodeoxycholate, tetralysine L-aspartic acid b-phosphatidyl-ethanolamine and tetralysine S-farnesyl-L-cysteine were prepared by solid-phase method then isolated, purificated and analitically characterized. Liposomes were prepared by REV-phase and extrusion; micelles were prepared by simple suspension in water of each CP. Afterwards they were characterized by size and charge using a Zetasizer, Malvern, UK. The obtained liposomes present an average diameter reflecting the pore size of the membrane used for the extrusion. After DNA complexation the mean diameter of complexes decreased by increasing the number of positive charges. The non-complexed liposome preparations showed a net positive zeta potential comprised between + 17.8 and + 30 mV. After adding Defibrotide (DFT) to liposomes (at a 1:4 +/- molar ratio) the zeta potential fell down to a net negative value indicating the formation of the ionic complex. Concerning micelles, before complexation it was not possible to measure their size by PCS. However, after DFT complexation the size of complexes highly increased. In addition, before complexation, the five CPs solutions showed a positive zeta potential ranging from +10 to +17.8 mV, while after addition of DFT the zeta potential fells to negative values. Taking into account these results, the studied CPs could be efficiently used to obtain both cationic liposomes and micelles. Moreover they are able to complex DNA with different interaction strength, depending on the type of peptide-based cationic molecule used.noneR. Cortesi; E. Esposito; M. Marastoni; E. Menegatti; C. NastruzziCortesi, Rita; Esposito, Elisabetta; Marastoni, Mauro; Menegatti, Enea; Nastruzzi, Claudi
