Growth of poly(2-hydroxyethyl methacrylate) brushes on magnetic nanoparticles and subsequent brush functionalization with nitrilotriacetate-Ni2+ yield magnetic beads that Selectively Capture polyhistidine-tagged (His tagged) protein directly from cell extracts. Transmission electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis, and magnetization measurements confirm and quantify the formation of the brushes on magnetic particles, and Multilayer protein adsorption to these brushes results in binding capacities (220 mg BSA/g of beads and 245 mg His tagged ubiquitin/g of beads) that are an order of magnitude greater than those of commercial magnetic beads. Moreover, the functionalized beads selectively capture His tagged protein within 5 min. The high binding capacity and protein purity along with efficient protein capture in a short incubation time make brush modified particles attractive for purification of recombinant proteins.