Magnetic targeting of iron-oxide-labeled fluorescent hepatoma cells to the liver

Abstract

The purpose of this study was to determine whether an external magnet field can induce preferential trafficking of magnetically labeled Huh7 hepatoma cells to the liver following liver cell transplantation. Huh7 hepatoma cells were labeled with anionic magnetic nanoparticles (AMNP) and tagged with a fluorescent membrane marker (PKH67). Iron-uptake was measured by magnetophoresis. Twenty C57Bl6 mice received an intrasplenic injection of 2 x 10(6) labeled cells. An external magnet (0.29 T; 25 T/m) was placed over the liver of 13 randomly selected animals (magnet group), while the remaining 7 animals served as controls. MRI (1.5 T) and confocal fluorescence microscopy (CFM) were performed 10 days post-transplantation. The presence and location of labeled cells within the livers were compared in the magnet group and controls, and confronted with histological analysis representing the standard of reference. Mean iron content per cell was 6 pg. Based on histology, labeled cells were more frequently present within recipient livers in the magnet group (p < 0.01) where their distribution was preferentially peri-vascular (p < 0.05). MRI and CFM gave similar results for the overall detection of transplanted cells (kappa = 0.828) and for the identification of peri-vascular cells (kappa = 0.78). Application of an external magnet can modify the trafficking of transplanted cells, especially by promoting the formation of perivascular aggregates.

Optical Imaging and Magnetic Field Targeting of Magnetic Nanoparticles in Tumors

“…However, other investigators have used constant external MF exposure of 2 h, 8 h, or 10 days, then immediately euthanized the animals after removing the MF because of concerns that removing the magnet might result in reversible accumulation of magnetic particles or magnetically labeled cells 28–30. Our study demonstrates that even if the MF is removed, the shorter exposure time was sufficient to significantly increase the accumulation evidenced by strong fluorescence signal intensity 24 h post injection.…”

Evaluation of Tumor Treatment of Magnetic Nanoparticles Driven by Extremely Low Frequency Magnetic Field

“…In particular, as MNPs can be manipulated by an external magnetic field9101112, their interaction with cells can be confined to targeted area to avoid any unwanted side effects. MNPs have been widely utilized in drug delivery131415, hyperthermia treatment for cancer16, magnetic targeting17, contrast agents in magnetic resonance imaging (MRI)18, cell labeling and sorting1920, and immunoassays21. Although extensive studies have demonstrated the relative biological safety of MNPs22232425, prior to build effective MNPs systems for various biomedical applications, their cytotoxicity and critical characteristics including size, structure, surface functionality, magnetic properties, stability, and dispensability2627 have to be taken into full investigation.…”

Cell labeling with magnetic nanoparticles: Opportunity for magnetic cell imaging and cell manipulation

“…If the viability is compromised, we have to disperse and administer cells by a syringe with a smaller gauge number (larger needle diameter). Nevertheless, even if administered cells are individualized, they might, under certain conditions, form perivascular aggregates within the body after magnetic guiding [45]. …”