(569b) Magnetically-Enabled Recovery of Beads in Microchannels: Quadrupole Magnet Flow Sorters As Enhanced System Design

Functionalized magnetic beads (MBs) have proven valuable to recover compounds (including toxins, metal ions, etc.) from complex media (e.g., biofluids) in microfluidic systems. Specifically, the retrieval of target compounds using functionalized MBs relies on their adsorption on the surface of the MBs, which results in the formation of target compound-MB complexes, and the subsequent recovery of these complexes by applying magnetic fields. Despite the promising prospects of this separation strategy, the small size of the particles makes challenging the recovery of the target compound-MB complexes in conventional Y-Y shaped microseparators that use a single permanent magnet to generate the magnetic field.^1,2 In this work, we address the computer-aided design and characterization of a quadrupole magnetic sorter (QMS), which consists of an annular microchannel surrounded by four permanent magnets arranged in quadrupolar orientation, in order to enhance the retrieval of MBs by increasing the driving force for such recovery (i.e., the magnetic force). For that purpose, a computational model that accounts for the magnetic and fluidic forces acting on the MBs was employed by linking an in-house Fortran code with the computational fluid dynamics (CFD) software Flow-3D. Our results revealed that compared to the conventional system, the complete recovery of either (a) MBs flowing at ≈ 360 times higher flow rates or (b) 2.2 times smaller MBs (particle diameter equal to 2.22 µm) can be successfully accomplished in the QMS. Collectively, the enhanced performance of the QMS has been demonstrated, thus, supporting the exploitation of these systems for the efficient magnetic recovery of target compounds from complex media.

References

[1] J. Gómez-Pastora, et al., Lab Chip. 18 (2018) 1593-1606.

[2] C. González-Fernández, et al., Ind. Eng. Chem. Res. 60 (2021) 16780-16790.