Separation via MagLev

Magnetic labels are widely used to aid in the separation and purification of chemical and biological samples. These labels typically consist of superparamagnetic nano- or microspheres, such as Invitrogen’s Dynabeads, which can be covalently attached to a variety of chemical and biological samples. For instance, immunomagnetic separation involves the use of antibodies, often monoclonal, bound to magnetic particles, enabling the removal of prokaryotic and eukaryotic cells from suspension. Various techniques, including cell separation, free flow magnetophoresis, and immunoassays, have been developed for integration into microfluidic devices for lab-on-a-chip technology. However, these magnetic labeling methods have certain limitations: (i) the separations are limited to binary outcomes, with magnetic particles being separated from diamagnetic particles; (ii) the labeling of a diamagnetic material requires a chemical reaction; (iii) the presence of a magnetic particle attached to a diamagnetic material, such as a cell, antibody, or protein, can alter the functionality and properties of the surface; and (iv) the magnetic label must be removed after separation to obtain a pure diamagnetic sample (Winkleman et al. in Anal Chem 79:6542–6550, 2007).