Magnetic nanoparticles have been widely developed as vectors in targeting drug and gene delivery. Disulfide-containing polyethylenimine derivative- (SSPEI-) functionalized magnetic carbon nanotubes (CNTs/Fe3O4-SSPEI) were synthesized as gene vector. Fourier transform infrared, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis were used to characterize CNTs/Fe3O4-SSPEI nanoparticles. The magnetic nanoparticles displayed typical superparamagnetic behavior and excellent dispersibility in water. Plasmid DNA could be bound by CNTs/Fe3O4-SSPEI to form the complexes. The sizes of complexes are about 400 nm, and the zeta potentials are positive at the w/w ratio over 6. CNTs/Fe3O4-SSPEI nanoparticles displayed higher transfection activity than did PEI (25 kDa), whereas the cytotoxicity was rather lower. Moreover, the transfection efficiency was further increased with the assistance of an external magnetic field. These results indicate that CNTs/Fe3O4-SSPEI nanoparticles would be a promising vector in targeted gene delivery.

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