Amphiphilic monomer of formula (I) Li-CΞC-CΞC-L2-X-Z (I)whereinL1 is CH3(CH2)m , with m being an integer from 1 to 24, L2 is -CH2(CH2)n-CONH-, with n being an integer from 1 to 24, X is -(CH2)t-O-(CH2CH2O)p(CH2)t-NH-, with t and t being independently from each other 2 or 3 and p being an integer from 2 to 500 and Z is H or a positively charged group selected from natural or non natural amino acid residues, carboxylated polyamines residues, and peptides comprising from 2 to 5 amino acids, at least one of said amino-acids being an histidine residue, their physiologically acceptable salts and their use in transfection and delivery methods.
