Elaboration of Superparamagnetic and Bioactive Multicore–Shell Nanoparticles (γ-Fe 2 O 3 @SiO 2 -CaO): A Promising Material for Bone Cancer Treatment

Abstract : The past few decades have seen the development of new bone cancer therapies, triggered by the discovery of new biomaterials. When the tumoral area is small and accessible, the common clinical treatment implies the tumor mass removal followed by bone reconstruction or consolidation with a bioceramic or a metallic scaffold. Even though the treatment also involves chemotherapy or radiotherapy, resurgence of cancer cells remains possible. We have thus designed a new kind of heterostructured nanobiomaterial, composed of SiO2-CaO bioactive glass as the shell and superparamagnetic γ-Fe2O3iron oxide as the core in order to combine the benefits of bone repair thanks to the glass bioactivity and of cancer cells destruction through magnetic hyperthermia (MH). These multifunctional core-shell nanoparticles (NPs) have been obtained using a two-stage procedure, involving the coprecipitation of 11 nm sized iron oxide NPs followed by their encapsulation inside a bioactive glass shell by sol-gel chemistry. The as-produced spherical multicore-shell NPs show a narrow size distribution of 73 ± 7 nm. Magnetothermal loss measurements by calorimetry under an alternating magnetic field and in vitrobioactivity assessment performed in SBF (Simulated Body Fluid) showed that these heterostructures exhibit a good heating capacity and a fast mineralization process (hydroxyapatite forming ability). In addition, their in vitrocytocompatibility, evaluated in the presence of Human Mesenchymal Stem Cells (h-MSCs) during 3 and 7 days, has been demonstrated. These firstfindings suggest that γ-Fe2O3@SiO2-CaO heterostructures are a promising biomaterial to fill bone defects resulting from bone tumors resection, as they have the ability to both repair bone tissue and to act as thermo-seeds for cancer therapy