Multicore flower-like magnetite for potential application in cancer nanomedicine

Abstract

Nanomaterials are intensively researched both from the fundamental aspect due to new properties at the nanoscale, as well as the aspect of their application in many areas of technology. Magnetic nanoparticles (MNPs) are being tested for use in the diagnosis and therapy of diseases. A new field of medicine, Magnetic nanomedicine is primarily based on the application of MNPs as drug carriers, diagnostic agents in Magnetic Resonance Imaging (MRI) and heat generators in magnetic hyperthermia. Among nanoparticles, magnetic nanoplatforms based on iron oxides for cancer diagnosis and therapy (Cancer nanomedicine) are the most researched and clinically tested. This study presents the results of research into the physicochemical properties of iron oxide nanoparticles prepared by the polyol route, as well as their testing for potential applications as agents in magnetic hyperthermia (MH) and radionuclide carriers (vectors) for the diagnosis and therapy of malignant diseases. Multicore iron oxide structures synthesized by the "polyol" method represent clusters of single-core nanoparticles or crystallites. The dimensions of the single core particles are \textasciitilde13.5 nm, while the nanoflowers formed by clustering are \textasciitilde25 nm, depending on the applied synthesis parameters. For targeted medical applications, nanoflowers are coated with different ligands in order to increase colloidal stability and biocompatibility. The best results were by coating MNPs with polyacrylic acid (PAA). The multifunctionality of nanoflowers was investigated by measuring their hyperthermic efficiency for applications in magnetic hyperthermia and radiolabeling with diagnostic (99mTc) and therapeutic radionuclides (177Lu, 90Y). In addition to traditional methods of cancer therapy (surgery, radiotherapy, and chemotherapy), new ways of therapy such as MH are constantly being developed. MH is a therapy based on the property of MNPs that when placed in an alternating (AC) magnetic field, transform the electromagnetic energy of the field into heat. When located inside a tumor, MNPs can locally generate a temperature of 42-46 °C and destroy cancer cells by heat. The hyperthermic efficiency of MNPs is expressed through the Intrinsic Loss Power (ILP) parameter. The measured ILP was 7.3 nHm2/kg which is considered one of the higher reported values found in the literature for iron oxides. Nanoflowers were radiolabeled with 99mTc, 177Lu, and 90Y radionuclides. The in vitro stability of radiolabeling was investigated. Good in vitro stability indicates that the formed radioactive particles can be used simultaneously for bi-modal cancer therapy (MH and radionuclide therapy) or for MH therapy and diagnostics (theranostics), in the case of labeling with 99mTc.