Enhanced magnetic particle transport by integration of a magnetic flux guide: Experimental verification of simulated behavior

In the past, magnetic biosensors have shown to be promising alternatives for classical fluorescence-based microarrays, replacing the fluorescent label by a superparamagnetic particle. While on-chip detection of magnetic particles is firmly established, research groups continue to explore the unique ability of manipulating these particles by applying controlled magnetic forces. One of the challenging tasks in designing magnetic force generating structures remains the generation of large forces for a minimal current consumption. Previously, a simple transporting device for single magnetic particles has been demonstrated using a magnetic field that is generated by two tapered current carrying conductors [R. Wirix-Speetjens, W. Fyen, K. Xu, J. De Boeck, and G. Borghs, IEEE Trans. Magn. 41(10), 4128 (2005)]. We also developed a model to accurately predict the motion of a magnetic particle moving in the vicinity of a solid wall. Using this model, we now present a technique that enhances the magnetic force up to a factor of 3 using a magnetic flux guide. The larger magnetic force results in an average speed of the particle which increases with a factor of 3. These simulations show good agreement with experimental results. (C) 2006 American Institute of Physics.