Magnetite-poly(lactic-co-glycolic acid) hybrid particles: Preparation and viscoelastic properties

Magnetite-poly(lactic-co-glycolic acid) (PLGA) hybrid particles were prepared by an emulsion–evaporation method (O/W single emulsion) in which magnetite nanoparticles were dispersed in the aqueous phase. The morphology of the resulting samples was determined through scanning electron microscopy (SEM and FESEM) which revealed the formation of core–shell particles because of the incorporation of magnetite nanoparticles on the surface of PLGA particles. Magnetite-PLGA hybrid particles present a much lower particle size than blank PLGA particles prepared under the same experimental conditions due to the effect of stabilization of the magnetite nanoparticles during the formation of the O/W emulsion. The main focus of the paper is the determination of the viscoelastic properties of aqueous dispersions of magnetite-PLGA hybrid materials as a means to elucidate the influence of the presence of magnetite nanoparticles on the rheological behaviour of the dispersions. Results have shown that aqueous dispersions of pristine PLGA particles and magnetite-PLGA particles present a very weak gel structure and that the presence of magnetite nanoparticles does not result in the increase of the elastic modulus of their aqueous dispersions.