Non-porous magnetic chelator supports for protein recovery by immobilised metal affinity adsorption

Micron-sized non-porous magnetic adsorbents derivatized with the metal chelating agent, iminodiacetic acid (IDA), have been prepared for the selective recovery of proteins. Four preparative routes employing epoxide activation
chemistry were investigated to introduce IDA onto the surface of polyglutaraldehyde-coated particles. The presence of surface bound IDA was demonstrated by the selective binding of Cu²⁺ and by the behaviour of Cu²⁺-charged and uncharged supports towards native haem proteins known to bind porous polymer-based Cu²⁺-IDA adsorbents. The simplest and most direct procedure was developed further. Supports prepared by this method were optimised with respect to ligand density and specific binding capacity. These coating and derivatization methods resulted in supports with a high level of substitution and low non-specific binding while retaining a high effective surface area for binding of the target protein ( > 200 mg g^-1). The resulting magnetic chelator supports possess excellent long term storage stability.