Turning biopolymer particles into hybrid capsules:: the example of silica/alginate nanocomposites

Several methods have already been developed for the design of (bio) polymer micro- and nanoparticles used in pharmaceutical science. In this paper, we demonstrate that some of these approaches can be easily adapted for the design of hybrid nanocapsules. A microgel route can be used for the synthesis of poly-L-lysine/alginate microparticles, that are further coated with silica, leading to micron sized core shell composites. Alternatively, a spray-drying technique is used for the one-pot synthesis of silica/poly-L-lysine/alginate nanocomposites that exhibit a homogeneous structure. As a consequence, the in situ reduction of Co2+ ions leads to the intra-capsular formation of magnetic cobalt silicates. When added to fibroblast cells, nanoparticles enter the intracellular space where they are degraded, suggesting that these new nanocomposites should be suitable for targeted drug delivery applications.