QμickBeads™: Magnetic isolation of rare stem cells via a capture and release platform

Magnet-activated cell sorting (MACS) is a well-developed and widely utilized method of isolating cells of interest in clinical medicine as well as basic biological science. In this technique, antibody-functionalized magnetic microbeads are utilized to bind to certain cell types in a heterogeneous suspension enabling subsequent separation by flow though a magnetic column. Separation can be accomplished by positive selection, where the cell type of interest is magnetically tagged and isolated, or by negative selection, where non-target cell types are tagged and extracted. MACS can provide extremely high purities (>95%) at high throughput (~10¹⁰ cells/hr) and is much more cost effective ($10k vs. $500k) than fluorescence-activated cell sorting (FACS). A major gap in MACS technology, particular relevant to the positive selection capture method, is the inability to detach the magnetic tag without significant loss of viability, phenotypic identity, and function. Such detachment capability is of critical importance in stem cell biology and regenerative medicine, where certain cell types are manipulated under highly defined conditions and may be ultimately implanted in vivo. We have designed a scaled releasable magnetic microbead kit (QuickBead^TM) capable of highly specific antibody-mediated adhesion to target cells and easy detachment. QuickBead^TM will provide the clinical and biomedical research community with the unique ability to selectively label and separate target cell populations from heterogeneous suspensions without the adverse consequence of retained magnetic beads on target cells.