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

Abstract

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

Acknowledgments

This work was partially aided by a grant from the National Science Council (NSC-98-2320-B-006-MY3), and National Cheng Kung University Hospital (NCKUH-10104020), Taiwan, through a contract awarded to SN Wu and DB Shieh. The authors would like to thank Pei-Yu Wu for providing RAW 264.7 cells, Tai-I Hsu for performing parts of the electrophysiological experiments, and Hsien-Ching Huang and Chia-Chen Yeh for their helpful assistance.

Disclosure

The authors report no conflicts of interest in this work.