Simple thermal treatment to improve the MRI and magnetic hyperthermia performance of hybrid iron Oxide-Mesoporous silica nanocarriers

Abstract

The design of multifunctional nanocomposites (NCs), incorporating a variety of controllable properties from nanostructured materials, spans their applicability as nanotools in biomedical applications. Santa Barbara Amorphous (SBA-15) mesoporous silica has showcased remarkable capabilities, ranging from bone regeneration to drug delivery. Its synergy with magnetic nanoparticles (MNPs) further broadens its scope as a theranostic agent, seamlessly integrating both therapeutic and diagnostic functions. However, efficiency issues arise due to MNP anchoring, necessitating novel solutions for optimization. This study focuses on enhancing the magnetic properties of hybrid iron oxide-SBA-15 mesoporous silica NCs through a simplified thermal procedure. The aim is to optimize their magnetic performance for dual functionality as contrast agents for magnetic resonance imaging (MRI) and as effective heaters in magnetic hyperthermia (MH) processes, while preserving the cylindrical mesoporous structure, high surface area, and high loading capacity compared to conventional ceramics. The investigation highlights that the impact of heat treatment on physicochemical properties varies depending on the compositions of the NCs. Specifically, the transversal relaxivity in MRI was doubled, accompanied by an enhanced Néel contribution in MH. This enhancement was achieved while maintaining the same biocompatibility as non-treated NCs, as demonstrated in evaluations with two cancer cell lines (HeLa and T-731 astrocytes), revealing low toxicity at concentrations up to 200 μg/mL.