Non-chemotoxic induction of cancer cell death using magnetic nanowires

Abstract

In this paper, we show that magnetic nanowires with weak magnetic fields and low frequencies can induce cell death via a mechanism that does not involve heat production. We incubated colon cancer cells with two concentrations (2.4 and 12 μg/mL) of nickel nanowires that were 35 nm in diameter and exposed the cells and nanowires to an alternating magnetic field (0.5 mT and 1 Hz or 1 kHz) for 10 or 30 minutes. This low-power field exerted a force on the magnetic nanowires, causing a mechanical disturbance to the cells. Transmission electron microscopy images showed that the nanostructures were internalized into the cells within 1 hour of incubation. Cell viability studies showed that the magnetic field and the nanowires separately had minor deleterious effects on the cells; however, when combined, the magnetic field and nanowires caused the cell viability values to drop by up to 39%, depending on the strength of the magnetic field and the concentration of the nanowires. Cell membrane leakage experiments indicated membrane leakage of 20%, suggesting that cell death mechanisms induced by the nanowires and magnetic field involve some cell membrane rupture. Results suggest that magnetic nanowires can kill cancer cells. The proposed process requires simple and low-cost equipment with exposure to only very weak magnetic fields for short time periods.

Cytotoxicity and intracellular dissolution of nickel nanowires

“…Similarly, an alternating current magnetic field has been proven to increase the inflammation of cells with internalized Ni NWs due to an increase in the pro-inflammatory cytokine interleukin-6 (Choi et al 2012). More recently, it has been shown that Ni NWs can be used to kill cancer cells with extremely low magnetic fields and frequencies (Contreras et al 2015).…”

Elongated Nanoparticle Aggregates in Cancer Cells for Mechanical Destruction with Low Frequency Rotating Magnetic Field

“…Compared to the micro-scale magnetic materials, nanomaterials are easily internalized by cells 39, and the intracellular cell membrane destruction has been proven to be more efficient than the disruption from the cell surface 23. Furthermore, the magnetic field in this study is safe and its frequency substantially lower than the risk level in adults 40.…”

Magnetic particles with perpendicular anisotropy for mechanical cancer cell destruction

“…We model this interaction using a quasi-static Stoner-Wohlfarth-like model 20, 21 . Usually, dynamic models are used 4, 14 , but the large torques involved here mean that the retarding effect of the fluid drag is negligible (see supplementary material) and so the particle is assumed to be able to reach the minimum energy configuration on the timescales of the experiment. In this model the energy for a magnetic disc of moment m is given by:where H is the applied field, H k is the anisotropy field, α is the angle of the applied field relative to the easy axis and θ is the angle of the magnetization relative to the easy axis.…”