Toxicity evaluation of magnetic hyperthermia induced by remote actuation of magnetic nanoparticles in 3D micrometastasic tumor tissue analogs for triple negative breast cancer

Magnetic hyperthermia as a treatment modality is acquiring increased recognition for loco-regional therapy of primary and metastatic lung malignancies by pulmonary delivery of magnetic nanoparticles (MNP). The unique characteristic of magnetic nanoparticles to induce localized hyperthermia in the presence of an alternating magnetic field (AMF) allows for preferential killing of cells at the tumor site. In this study we demonstrate the effect of hyperthermia induced by low and high dose of MNP under the influence of an AMF using 3D tumor tissue analogs (TTA) representing the micrometastatic, perfusion independent stage of triple negative breast cancer (TNBC) that infiltrates the lungs. While application of inhalable magnetic nanocomposite microparticles or magnetic nanocomposites (MnMs) to the micrometastatic TNBC model comprised of TTA generated from cancer and stromal cells, showed no measureable adverse effects in the absence of AMF-exposure, magnetic hyperthermia generated under the influence of an AMF in TTA incubated in a high concentration of MNP (1 mg/mL) caused significant increase in cellular death/damage with mechanical disintegration and release of cell debris indicating the potential of these inhalable composites as a promising approach for thermal treatment of diseased lungs. The novelty and significance of this study lies in the development of methods to evaluate in vitro the application of inhalable composites containing MNPs in thermal therapy using a physiologically relevant metastatic TNBC model representative of the microenvironmental characteristics in secondary lung malignancies.

Magnetic nanoparticles and nanocomposites for remote controlled therapies

This review highlights the state-of-the-art in the application of magnetic nanoparticles (MNPs) and their composites for remote controlled therapies. Novel macro- to nano-scale systems that utilize remote controlled drug release due to actuation of MNPs by static or alternating magnetic fields and magnetic field guidance of MNPs for drug delivery applications are summarized. Recent advances in controlled energy release for thermal therapy and nanoscale energy therapy are addressed as well. Additionally, studies that utilize MNP-based thermal therapy in combination with other treatments such as chemotherapy or radiation to enhance the efficacy of the conventional treatment are discussed.

Formulation and characterization of inhalable magnetic nanocomposite microparticles (MnMs) for targeted pulmonary delivery via spray drying

Targeted pulmonary delivery facilitates the direct application of bioactive materials to the lungs in a controlled manner and provides an exciting platform for targeting magnetic nanoparticles (MNPs) to the lungs. Iron oxide MNPs remotely heat in the presence of an alternating magnetic field (AMF) providing unique opportunities for therapeutic applications such as hyperthermia. In this study, spray drying was used to formulate magnetic nanocomposite microparticles (MnMs) consisting of iron oxide MNPs and d-mannitol. The physicochemical properties of these MnMs were evaluated and the in vitro aerosol dispersion performance of the dry powders was measured by the Next Generation Impactor(®). For all powders, the mass median aerosol diameter (MMAD) was <5μm and deposition patterns revealed that MnMs could deposit throughout the lungs. Heating studies with a custom AMF showed that MNPs retain excellent thermal properties after spray drying into composite dry powders, with specific absorption ratios (SAR)>200W/g, and in vitro studies on a human lung cell line indicated moderate cytotoxicity of these materials. These inhalable composites present a class of materials with many potential applications and pose a promising approach for thermal treatment of the lungs through targeted pulmonary administration of MNPs.