Formation and characterization of natural polysaccharide hollow nanocapsules via template layer-by-layer self-assembly

With natural polysaccharides carrageenan (Car) and chitosan (Cs) as the polyanion and polycation, respectively, multilayer hollow nanocapsules have been fabricated via sequential layer-by-layer (LbL) electrostatic self-assembly from the sacrificed templates nanospheres (SiO2-NH2). The LbL assembly process with the polysaccharides on SiO2-NH2 core was followed by zeta-potential and size analysis. The fabrication of (Car/Cs)(x) nanocapsules and the removing of the SiO2-NH2 core templates were confirmed by TGA and EDS analysis. The morphology of SiO2(Car/Cs)(x) nanospheres and (Car/Cs)(x) nanocapsules were observed by TEM analysis. The size analysis of (Car/Cs)(x) nanocapsules indicated that the cyst wall thickness and cavity volume of the nanocapsules are pH and ionic strength dual responsive. Due to the biocompatibility of the natural polysaccharides carrageenan and chitosan and the responsiveness of nanocapsules to pH and ionic strength, the (Car/Cs)(x) multilayer nanocapsules are expected to be used as nanoreactors or nanocontainers to control the synthesis, encapsulation, and releasing behaviors of bioactive molecules. (C) 2012 Elsevier Inc. All rights reserved.