Design and fabrication of novel core-shell nanoparticles for theranostic applications

Superparamagnetic iron oxide nanoparticles (SPIONs) were prepared by co-precipitation method, functionalized respectively with tetraethyl orthosilicate (TEOS) and 3-(trimethoxysilyl)propyl methacrylate (TMSPM), and monodispersed by filtration and centrifugation. The vinyl-functionalized monodispersed SPIONs were then coated with a shell of the novel dual-responsive hydrogel having semi-interpenetrating polymer network (semi-IPN) structure. The formulation of this hydrogel, which was designed and synthesized in the previous study, was based on sodium alginate (Alg-Na) polymer and temperature-sensitive N-isopropylacrylamide (NIPAA) and pH-sensitive N-ethylmaleamic acid (NEMA) monomers. Sodium alginate acting as a pore-forming agent has a key role in the generation of semi-IPN structure and significantly decreases the time to reach the equilibrium swelling. Totally, two series of core-shell nanoparticles (CSNs) with the same magnetic core and different shell thicknesses were fabricated and exposed to different tests including transmission electron microscopy (TEM), dynamic light scattering (DLS), magnetic property evaluations, and magnetic resonance imaging (MRI) measurements. The obtained results of these tests revealed that these CSNs have the potential to be used as new theranostic platforms for simultaneous cancer diagnosis and therapy. Graphical abstract