Multifunctional Containers from Anionic Liposomes and Cationic Polymers/Colloids

The study describes an “open” method for concentrating anionic bilayer lipid vesicles (liposomes) locally by electrostatically binding them in a complex with cationic polymers. This method is implemented by mixing premade solutions of liposomes and polymers, which significantly reduces the time and cost of obtaining multiliposomal complexes. Binding of liposomes with cationic linear polymers, latexes, and star polymers does not solve the problem of obtaining multiliposomal complexes: the size of such complexes cannot be controlled, and these variants fail to ensure the integrity of bound liposomes or result in complexes with a minimal amount of liposomes. The best results are demonstrated by complexes of anionic liposomes and polystyrene nanoparticles with grafted cationic chains (spherical polycationic brushes). Each brush can bind several dozen liposomes, which retain their integrity after being adsorbed on the surface of the brush. Such complexes do not dissociate into the initial components either in physiological saline with [NaCl] = 0.15 mol/L or in the presence of significant amounts of protein. The use of liposomes with different fillers (different liposomal “compartments”) makes it possible to obtain multiliposomal complexes with the desired fraction of substances encapsulated in the liposomes. The proposed approach is of interest in terms of obtaining multiliposomal complexes for concentration, compartmentalization, and subsequent controlled release of drugs.