Abstract
A comprehensive totally aqueous phase synthesis of nickel-nitrilotriacetate (Ni-NTA) modified superparamagnetic Fe 3 O 4 nanoparticles is presented. The Fe 3 O 4 -NTA-Ni nanoparticles are able to perform efficient and specific purification of 6-His tagged proteins from crude cell lysates, as evidenced by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. The average binding capacity, as demonstrated by streptopain (M W 42kDa), is 0.23mg/mg (protein/Fe 3 O 4 -NTA-Ni). Considering the high affinity and specificity of the binding between hexahistidine motif and Ni-NTA, Ni-NTA modified nanoparticles could act as a module to carry 6-His tagged proteins on the particle surface with molecular orientation control, since only the 6-His domain could be attached. These modularly designed functional nanoparticles enhance cancer cell targeting, as supported by the in vitro receptor mediated targeting assay using RGD-4C-6-His fusion peptide. The nanoparticles show no significant hemolysis for human blood and could be investigated further for their in vivo functional imaging applications. © 2006 IOP Publishing Ltd.