Gd-Doped Superparamagnetic Magnetite Nanoparticles for Potential Cancer Theranostics

Abstract

Nanotechnology has facilitated the applications of a class of nanomaterials called superparamagnetic iron oxide nanoparticles (SPIONs) in cancer theranostics. This is a new discipline in biomedicine that combines therapy and diagnosis in one platform. The multifunctional SPIONs, which are capable of detecting, visualizing, and destroying the neoplastic cells with fewer side effects than the conventional therapies, are reviewed in this chapter for theranostic applications. The chapter summarizes the design parameters such as size, shape, coating, and target ligand functionalization of SPIONs, which enhance their ability to diagnose and treat cancer. The review discusses the methods of synthesizing SPIONs, their structural, morphological, and magnetic properties that are important for theranostics. The applications of SPIONs for drug delivery, magnetic resonance imaging, and magnetic hyperthermia therapy (MHT) are included. The results of our recent MHT study on Gd-doped SPION as a possible theranostic agent are highlighted. We have also discussed the challenges and outlook on the future research for theranostics in clinical settings.

The Role of Magnetic Nanoparticles in Cancer Nanotheranostics

“…An extensive variety of synthesis methods have been implemented for the development of MNPs, using physical or chemical synthesis approaches. Accordingly, methods such as mechanical attrition, thermal decomposition, hydrothermal synthesis, sol-gel reaction, microemulsion, coprecipitation, sonolysis, electrochemical method and polyol method are some of the most relevant mentioned in the literature [17,19,20].…”

“…MNPs exist in several formations, namely spheres, rods, disks, wires, cubes, triangles, polyhedrons, gels, cages, flower-like structures, among others [19,20,51]. Due to the reduced dimensions, they assume a high surface area to volume ratio and express high aspect ratio values.…”

“…Magnetic properties have been identified as shape and composition-dependent on MNPs, such as maghemite rods, ferrite cubes, cobalt disks, Ni-Fe wires and Au-MnO flower-shaped nanoparticles [19]. The correlation between these two parameters is due to the shape anisotropy influence on the orientation of the magnetic moments of the particles.…”

“…The shape-induced magnetic anisotropy interferes with magnetization reversal due to thermal fluctuations and affects the heating efficiency of NPs [52]. On this basis, higher heating capacity and magnetization saturation values have been associated and demonstrated in cubic ferrite MNPs (of lower surface anisotropy) when compared to spherical MNPs of the same size [19,27,53].…”

“…T2 contrast agents, such as superparamagnetic nanoparticles (e.g., SPIONs), generate local magnetic fields that interfere and reduce the transverse relaxation time, resulting in a darker signal. Spherical nanocomposites combining both contrast agents, dextran-coated SPIONs with Gd ions inserted in the external MNP structure, have been synthesized by co-precipitation with Gd (III) nitrate for dual-modal imaging [19]. The Gd-doped system presented a nano-sized platform not only for MRI but also for hyperthermia therapy, making use of the relaxation energy loss in the form of heat to induce cell damage, that is intended to address the tumour tissue [19].…”