Micelles-encapsulated microcapsules for sequential loading of hydrophobic and water-soluble drugs

Layer-by-layer (LbL) assembly was conducted on CaCO(3) microparticles pre-doped with polystyrene-block-poly(acrylic acid) (PS-b-PAA) micelles, and resulted in micelles encapsulation in the microcapsules after core removal. Distribution of the micelles in the templates and capsules was characterized by transmission electron microscopy and confocal laser scanning microscopy. The micelles inside the capsules connected with each other to form a chain and network-like structure with a higher density near the capsule walls. The hydrophobic PS cores were then able to load small uncharged hydrophobic drugs while the negatively charged PAA corona could induce spontaneous deposition of water-soluble positively charged drugs such as doxorubicin.