Biofunctionalized magnetic-vortex microdiscs for targeted cancer-cell destruction

Abstract

Nanomagnetic materials offer exciting avenues for probing cell mechanics and activating mechanosensitive ion channels, as well as for advancing cancer therapies. Most experimental works so far have used superparamagnetic materials. This report describes a first approach based on interfacing cells with lithographically defined microdiscs that possess a spin-vortex ground state. When an alternating magnetic field is applied the microdisc vortices shift, creating an oscillation, which transmits a mechanical force to the cell. Because reduced sensitivity of cancer cells toward apoptosis leads to inappropriate cell survival and malignant progression, selective induction of apoptosis is of great importance for the anticancer therapeutic strategies. We show that the spin-vortex-mediated stimulus creates two dramatic effects: compromised integrity of the cellular membrane, and initiation of programmed cell death. A low-frequency field of a few tens of hertz applied for only ten minutes was sufficient to achieve ~90% cancer-cell destruction in vitro.

Chirality control via double vortices in asymmetric Co dots

“…10 Vortices are one type of topological defects characterized by an in-plane magnetization with a clockwise (CW) or counter-clockwise (CCW) chirality and a central core with an out-of-plane magnetization (up or down polarity).…”

Tailoring Staircase-like Hysteresis Loops in Electrodeposited Trisegmented Magnetic Nanowires: a Strategy toward Minimization of Interwire Interactions

“…31 Nevertheless, their exceedingly small surface area limits their efficiency as drug carriers. An alternative approach is to use magnetic vortices, 34 also with virtually zero magnetic remanence, but disks of a few micrometers in diameter are needed to form such magnetic configurations. Hence, magnetic vortices can be rather impractical for most biological purposes.…”

Effect of Varying Magnetic Fields on Targeted Gene Delivery of Nucleic Acid-Based Molecules

“…In terms of overcoming these inconveniences, magnetofection provides an alternative way of targeted gene delivery using magnetic fields. As a result, many studies related to gene delivery via magnetofection are now available in the literature [1][2][3][4][5][6][7][8][9][10][11]. For example, Scherer et al…”

“…The results indicated that the transfection efficiency was significantly enhanced due to simultaneous exposure of cells to ultrasound and magnetic field. Kim et al [9] reported on the interfacing of whole cells with biocompatible lithographically defined ferromagnetic microdiscs with a spin-vortex ground state. It was found that spin-vortexmediated stimulus caused compromised integrity of cellular membranes and initiation of programmed cell death.…”