Method of preparing silica nanocapsules and silica nanocapsules

A method of preparing substantially lens-shaped cargo-loaded silica nanocapsules, the method comprising:

• mixing a surfactant with water at a temperature that is above the gel-to-liquid transition temperature of the surfactant to form a mixture, the surfactant being selected from the group consisting of tetra alkyl ammonium halide;
• dimethyldioctadecylammonium bromide (DODAB);
• dimethyldioctadecylammonium chloride (DODAC);
• sulfate, phosphate or acetate salt of dimethyldioctadecylammonium (DODAX);
• dimethyldioctadecenylammonium bromide (DDAB);
• dimethyldioctadecenylammonium chloride (DDAC);
• sulfate, phosphate, acetate salt of dimethyldioctadecenylammonium (DDAX);
• bromide, chloride, sulfate, phosphate or acetate salt of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP);
• bromide, chloride, sulfate, phosphate or acetate salt of 1,2-dioleoyl-3-dimethylammonium propane (DODAP);
• bromide, chloride, sulfate, phosphate or acetate salt of N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium (DOTMA), and combinations thereof;
• passing the mixture one or more times through at least one pore to obtain a dispersion of vesicles;
• adding a silica precursor to the dispersion of vesicles to form substantially lens-shaped silica nanocapsules, the silicon precursor being selected from the group consisting of tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), tetrapropyl orthosilicate (TPOS), tetrabutyl ortho silicate (TBOS) and combinations thereof;
• and
• mixing one or more types of hydrophilic cargo molecules with the substantially lens-shaped silica nanocapsules in the presence of a first organic solvent prior to adding a second organic solvent, to load the one or more types of hydrophilic cargo molecules into the substantially lens-shaped silica nanocapsules thereby obtaining substantially lens-shaped cargo-loaded silica nanocapsules,
• wherein the one or more types of hydrophilic cargo molecules is miscible with the first organic solvent,
• wherein the one or more types of hydrophilic cargo molecules is not miscible with the second organic solvent and
• wherein the first and second organic solvents are miscible with each other.