[Peer Reviewed Manuscript]
Description: The growth of the biopharmaceutical industry has created a demand for new technologies for the purification of genetically engineered proteins. High gradient magnetic separation (HGMS) is a technology that has the potential to increase the speed of traditional affinity chromatography due to its use of an expanded bed of superparamagnetic microparticles (SPM). The efficiency of large-scale HGMS could be improved if SPMs offering higher binding capacityand magnetization were available. This article describes several strategies for synthesizing SPMs that are composed of a M13 bacteriophage layer assembled on a superparamagnetic core. Chemically cross-linking the pVIII proteins to a carboxyl functionalized SPM produced highly responsive superparamagnetic particles with a side-on oriented, adherent virus monolayer. Also, the genetic manipulation of the pIII proteins with a His6 peptide sequence allowed reversible assembly of the bacteriophage on a nitrilotriacetic acid functionalized core in an end-on configuration. These phage-SPMs were successfully used to separate antibodies from high-protein concentration solutions in a single step with a > 90 % purity. The dense SPM core of these particles makes them five times more responsive to magnetic fields than commerical materials and a monolayer of phage could produced a 1000 fold higher antibody binding capacity. These new bionanomaterials appear to be well-suited to large-scale HGMS separation and promise to be cost effective as a result of the self- assembling and self-replicating properties of genetically engineered M13 bacteriophage.