title: M13 bacteriophage-activated superparamagnetic beads for affinity separation.
abstract: The growth of the biopharmaceutical industry has created a demand for new technologies for the purification of genetically engineered proteins.The efficiency of large-scale, high-gradient magnetic fishing could be improved if magnetic particles offering higher binding capacity and magnetization were available. This article describes several strategies for synthesizing microbeads that are composed of a M13 bacteriophage layer assembled on a superparamagnetic core. Chemical cross-linking of the pVIII proteins to a carboxyl-functionalized bead produces highly responsive superparamagnetic particles (SPM) with a side-on oriented, adherent virus monolayer. Also, the genetic manipulation of the pIII proteins with a His(6)  peptide sequence allows reversible assembly of the bacteriophage on a nitrilotriacetic-acid-functionalized core in an end-on configuration. These phage-magnetic particles are successfully used to separate antibodies from high-protein concentration solutions in a single step with a >90% purity. The dense magnetic core of these particles makes them five times more responsive to magnetic fields than commercial materials composed of polymer-(iron oxide) composites and a monolayer of phage could produce a 1000 fold higher antibody binding capacity. These new bionanomaterials appear to be well-suited to large-scale high-gradient magnetic fishing separation and promise to be cost effective as a result of the self-assembling and self-replicating properties of genetically engineered M13 bacteriophage.
authors.affiliation: UCD Centre for Nanomedicine, School of Chemistry & Chemical Biology - University, College Dublin Belfield, Dublin 4, Ireland.
authors.forename: Julien
authors.initials: J
authors.lastname: Muzard
authors.forename: Mark
authors.initials: M
authors.lastname: Platt
authors.forename: Gil U
authors.initials: GU
authors.lastname: Lee
mesh_terms: D017104:Bacteriophage M13 / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D008280:Magnetics; D008863:Microspheres; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D015202:Protein Engineering / Q000379:methods
chemical_list: D001672:Biocompatible Materials