The effects of magnetite (Fe₃O₄) nanoparticles on electroporation-induced inward currents in pituitary tumor (GH₃) cells and in RAW 264.7 macrophages

Yen-Chin Liu¹, Ping-Ching Wu², Dar-Bin Shieh^2–5, Sheng-Nan Wu<sup>3,6,7

1</sup>Department of Anesthesiology, ²Institute of Oral Medicine and Department of Stomatology, ³Department of Physiology, National Cheng Kung University Hospital, College of Medicine, ⁴Advanced Optoelectronic Technology Center, ⁵Center for Micro/Nano Science and Technology, National Cheng Kung University, ⁶Innovation Center for Advanced Medical Device Technology, National Cheng Kung University, ⁷Department of Anatomy and Cell Biology, National Cheng Kung University Medical College, Tainan, Taiwan

Aims: Fe₃O₄ nanoparticles (NPs) have been known to provide a distinct image contrast effect for magnetic resonance imaging owing to their super paramagnetic properties on local magnetic fields. However, the possible effects of these NPs on membrane ion currents that concurrently induce local magnetic field perturbation remain unclear.
Methods: We evaluated whether amine surface-modified Fe₃O₄ NPs have any effect on ion currents in pituitary tumor (GH₃) cells via voltage clamp methods.
Results: The addition of Fe₃O₄ NPs decreases the amplitude of membrane electroporation-induced currents (I_MEP) with a half-maximal inhibitory concentration at 45 µg/mL. Fe₃O₄ NPs at a concentration of 3 mg/mL produced a biphasic response in the amplitude of I_MEP, ie, an initial decrease followed by a sustained increase. A similar effect was also noted in RAW 264.7 macrophages.
Conclusion: The modulation of magnetic electroporation-induced currents by Fe₃O₄ NPs constitutes an important approach for cell tracking under various imaging modalities or facilitated drug delivery.

Keywords: iron oxide, ion current, free radical