Using thiophilic magnetic beads in purification of antibodies from human serum.

The rapid progress of biotechnology, immunology and molecular biology are requiring antibodies with higher purity and stronger activity. Therefore, the development of efficient technology, which is suitable for large-scale purification of antibodies at low cost, becomes much more urgent. In this study, we presented a novel method to isolate immunoglobulin G from human serum based on the utilization of thiophilic magnetic polymer beads. Micron-sized magnetic beads with paramagnetic properties were synthesized by microsuspension polymerization in the presence of modified magnetite. After the thiophilic ligand of 2-mercaptonicotinic acid was modified on the surface, these magnetic beads exhibited a strong specificity towards immunoglobulin G in a salt-independent manner. Then, antibodies could be directly isolated from human serum in batch-wise mode with the assistance of magnetic decantation. The purity of the isolated antibody exceeded 94%. Because isolation was performed in physiological conditions, bioactivity of the antibody was fully preserved (>99%). Prominent advantages of this method, such as strong specificity, rapid processing, mild conditions, conventional equipment and excellent reusability, make this non-chromatographic technology embody great potentialities to isolate the antibodies on a large scale.