Fluorescence-based multimodal imaging for in vivo tracking of magnetite Janus nanoparticles as potential carriers for DOX under the alternating magnetic field: Enhancing tumor penetration

Abstract

Glioblastoma multiforme (GBM) is highly heterogeneous and poses significant challenges for delivering chemotherapeutic agents, primarily due to barriers like the blood-brain barrier (BBB) and the blood-brain tumor barrier (BBTB). This study hypothesizes that an alternating magnetic field (AMF) can influence the interaction between magnetic nanoparticles (MNPs) and cells, enhancing drug delivery to the brain as a magnetically guided therapy. We synthesized Janus iron oxide nanoparticles (MJNPs) that are dual conjugated with fluorescein dye (FL) for tracing, folic acid (FA) for active targeting, and doxorubicin (DOX), resulting in the formulation (DOX/MJNPs-FLA). The morphological properties of DOX/MJNPs-FLA were evaluated using various bio-physicochemical methods, including high-resolution transmission electron microscopy (HR-TEM), zeta potential analysis, and dynamic light scattering (DLS). The biosafety and biocompatibility of the nanoparticles were evaluated using the MTT test, hemolytic activity assay, and enzyme level analysis for liver and kidney function. The release of DOX from the nanoparticles was monitored using high-performance liquid chromatography (HPLC) in a rabbit model. Additionally, we evaluated the effect of applying an AMF on the rate at which nanoparticles cross the BBB and their accumulation in tumor cells through fluorescent imaging, Prussian blue staining, and inductively coupled plasma optical emission spectroscopy (ICP-OES). The results demonstrated that bio-safe DOX/MJNPs-FLA nanoparticles, measuring 80 nm, are capable of effective tracking, and sustained DOX release in vivo. Furthermore, drug delivery to the brain was significantly enhanced when a constant magnetic field (MF) and folic acid ligand were employed, indicating an active ligand/receptor mechanism compared to the control (p < 0.01). Continuing the application of the AMF further enhanced the effects of both the MF & FA, resulting in the highest accumulation of nanoparticles in the tumor, as evidenced by ICP-OES results and microscopic imaging. The findings suggest that an AMF can improve the delivery of MNPs across cell barriers and enhance the uptake of nanoparticles into cells and tissues. Moreover, the hyperthermia induced by the AMF activation MJNPs-FLA may increase the permeability of the BBB, potentially improving therapies aimed at diagnosing and treating various brain diseases.