Nitrilotriacetic acid-modified magnetic nanoparticles as a general agent to bind histidine-tagged proteins

Using Nα,Nα-bis(carboxymethyl)lysine to react with FePt magnetic nanoparticles, we synthesized the FePt−NTA conjugate, which immobilizes Ni2+ ions and selectively binds to histidine-tagged proteins at concentration as low as 0.5 pM. This simple system serves as a useful alternative to existing protocols for protein separation and also acts as a versatile agent for transporting and anchoring proteins.