Biomimetic core-shell gelatine/silica nanoparticles:: a new example of biopolymer-based nanocomposites

Hybrid nanoparticles have great potential for biotechnological and biomedical applications. It was recently proposed that biopolymer/silica nanomaterials could be easily obtained by adapting traditional routes used in pharmaceutical science to design polymer nanoparticles. In this paper, we demonstrate that core - shell gelatine/silica nanoparticles can be obtained using a nano-emulsion route, taking advantage of the thermal gelation properties of the biopolymer and of its strong "biomimetic'' affinity for silicates. The formation of the silica coating could be ascertained by SEM, TEM, EDAX, FTIR and DLS/zeta potential measurements. Silica coating was also performed on microparticles, allowing us to investigate in more detail the mechanism of silica deposition on the gelatine surface, which bears some relevance for the understanding of biosilicification processes. Finally, the possible internalization and intracellular degradation of these hybrid nanoparticles by fibroblast cells was demonstrated. A comparison with previously described silica/alginate nanoparticles is provided in the context of drug-delivery system design.