Design of Magnetic Gelatine/Silica Nanocomposites by Nanoemulsification: Encapsulation versus in Situ Growth of Iron Oxide Colloids.

Joachim Allouche,Michel Boissière,Corinne Chanéac,Thibaud Coradin,Roberta Brayner

doi:10.3390/nano4030612

Abstract

The design of magnetic nanoparticles by incorporation of iron oxide colloids within gelatine/silica hybrid nanoparticles has been performed for the first time through a nanoemulsion route using the encapsulation of pre-formed magnetite nanocrystals and the in situ precipitation of ferrous/ferric ions. The first method leads to bi-continuous hybrid nanocomposites containing a limited amount of well-dispersed magnetite colloids. In contrast, the second approach allows the formation of gelatine-silica core-shell nanostructures incorporating larger amounts of agglomerated iron oxide colloids. Both magnetic nanocomposites exhibit similar superparamagnetic behaviors. Whereas nanocomposites obtained via an in situ approach show a strong tendency to aggregate in solution, the encapsulation route allows further surface modification of the magnetic nanocomposites, leading to quaternary gold/iron oxide/silica/gelatine nanoparticles. Hence, such a first-time rational combination of nano-emulsion, nanocrystallization and sol-gel chemistry allows the elaboration of multi-component functional nanomaterials. This constitutes a step forward in the design of more complex bio-nanoplatforms.

Highlights

The design of particles containing iron oxide colloids has become an intense field of research due to their large potentialities for biomedical applications [1,2,3]
We have previously described the synthesis of hybrid gelatine/silica nanocomposites using a nano-emulsification approach [30]
Foreseeing further developments of hybrid magnetic biopolymer/silica nanoparticles for in vivo applications, where the stability in physiological fluids and/or organ targeting will require surface functionalization [49], we have evaluated the suitability of NPGMSi nanocomposites for surface modification

Summary

Introduction

The design of particles containing iron oxide colloids has become an intense field of research due to their large potentialities for biomedical applications [1,2,3]. The second one involves the preparation of the host particles containing Fe2+ and/or Fe3+ ions, followed by the in situ precipitation of iron oxide [24,25,26,27]. In this context, we have previously proposed a new family of nanocomposites, named hybrid magnetic carriers (HYMAC), consisting of biopolymer/silica nanoparticles incorporating magnetic colloids [28]. Alginate/silica and gelatine/silica hybrid nanomaterials could be obtained by adapting traditional routes used in pharmaceutical science to design polymer nanoparticles [29,30] These nanocomposites showed an enhanced thermal stability when compared to their biopolymer equivalents. Lowering the process temperature led to a decrease in silica condensation, affecting the hybrid nanoparticle stability [32]

Methods

Discussion

Conclusion