Interfacial deposition of functionalized copolymers onto nanoemulsions produced by the solvent displacement method

Cationic nanoemulsions containing an oily core as potential carriers of nuc leic acids were prepared by a solvent displacement method in the presence o f a nonionic surfactant (Pluronic F68). With a view to functionalize such n anoemulsions for further incorporation of a fusogenic peptide, a poly(malei c anhydride-ali-methyl vinyl ether) (M-n = 67,000) grafted with variable am ount of acetylspermine (or acetylspermidine) and decylamine was nanodeposit ed during the nanoemulsion formation step. Functionalized nanoemulsions wer e characterized in terms of particle size (by quasi-elastic light scatterin g and electron microscopy), electrophoretic mobility and long-term stabilit y as a function of the amount of polymer used in the formulation. It was fo und that increases in the level of the copolymer led to a reduction in the particle size and a decrease in colloidal stability. In addition, the incor poration of the grafted copolymers at the interface of the nanoemulsions wa s clearly evidenced, a shift towards low pH at the point of zero charge bei ng attributed to the formation of carboxylic groups induced by hydrolysis o f the residual maleic anhydride groups of the copolymer.