Magnetophoretic force and homogeneity optimization in multiplexed magnetic tweezers for microrheometry applications

In order to generate homogeneous magnetophoretic forces, current magnetic tweezer devices operate placing electromagnetic inductors far enough from the sample. Consequently, high-power supplies are needed to reach sufficiently large forces. We demonstrate that both magnetophoretic force magnitude and homogeneity can be increased at will in this kind of devices by simply placing appropriate magnetic materials between the inductors and the sample. Choice of these material shape and location is made upon an extensive optimization process performed with finite element method simulations. Optimal configuration is shown to create large and homo-geneous magnetophoretic forces over areas extensive enough to perform multiplexed microrheology tests with different values of force and pulse duration. A good correspondence is obtained between the experiment and the results from the simulations.

Automated summary

In this study, we demonstrate the control of magnetophoretic force magnitude and homogeneity by placing appropriate magnetic materials between the electromagnetic inductors and the sample. Through optimization, large and homogeneous magnetophoretic forces can be generated over a wide area for multiplexed microrheology tests.