Application of Cup Shaped Superparamagnetic Hemispheres for Size Selective Cell Purification

Abstract

Purification of specific target cells from complex cell ensemble is essential step in life science studies. Magnetic cell sorting (MACS) is one famous method to purify target cells depending on the specific recognition of ligands immobilized on the magnetic particles against the target cell. For the improvement of this method, one useful way is target cell recognition with not only ligand specificity but also other physical parameters. Here we report another way for the recognition and purification of target cells depending on their sizes using a new type magnetic particle.The particle was fabricated as follows. Polystyrene spheres were used as templates, coated with magnetic elements (Ni was used in this study) by thermal evaporation, and burned to remove polystyrene templates. Then, cup-shaped hemispheres composed of the evaporated elements were obtained. We succeeded for the fabrication of superparamagnetic hemispheres (referred as hereafter) by controlling the thickness of magnetic element layers strictly. Target cells were size-selectively captured into the inner cavity of the Mag cups, and easily collected with an application of the magnetic field. We found that the cells can be only collected using larger cups than target cell diameter, indicated that fabricated Mag cups can be used for size-selective cell purifications.