Magnetic nanowire-enhanced optomagnetic tweezers

We present an optomagnetic tweezers technique that utilizes the highly localized magnetic field gradients generated near the tip of a magnetic nanowire to provide strong trapping forces on magnetic nanoparticles with high spatial resolution. Integral to the approach is a method to trap, translate, and rotate a single magnetic nanowire in three dimensions; this nanowire is in turn capable of exerting forces on magnetic nanoparticles. Our simulation predicts that forces in the range of 100 pN can be generated on 200 nm magnetic particles within a distance of 0.3 µm from a 200 nm diameter nickel nanowire, magnetized to saturation. Such forces are relevant in many biological processes, suggesting this approach may be of value in biophysical studies.