A Novel Method to Construct Dual-targeted Magnetic Nanoprobes by Modular Assembling

Magnetic nanoparticle is an important branch of nanomaterials, especially magnetic iron oxide (Fe 3 O 4 ) nanoparticles have attracted widespread attention due to the fact that they can be used not only as high-sensitivity magnetic resonance contrast agents, but also as carriers for the construction of multifunctional and intelligent nanoprobes. The functional ligands modified on the surface of nanoprobes always provide the effective targeting ability. However, during the coupling process, the competitive inhibition of different modified ligands probably affects the construction of nanoprobes. Therefore, a modular designed method to construct magnetic nanoprobes is proposed in this paper and this method provides the favorable coupling efficiency and activity of the modified ligands as well as the inconspicuous competitive coupling effect between different ligands. The nanoprobes are composed of streptavidin modified Fe 3 O 4 nanoparticles and the biotinylated functional ligands assembled on the nanoparticles. Due to the specific binding between streptavidin and biotin, the functional ligands are coupled on the Fe 3 O 4 nanoparticles and the different ligands could be simply replaced to construct the nanoprobes with different function. Two types of dual-targeted nanoprobes including CD20&CD3@Fe 3 O 4 and E5&CD3@Fe 3 O 4 are synthesized. These nanoprobes have the appropriate hydrodynamic size (∼20 nm) and desirable magnetic properties (about 240 mM -1 s -1 for r 2 relaxivity). In cell experiments, CD20&CD3@Fe 3 O 4 and E5&CD3@Fe 3 O 4 showed strong cytotoxicity for Raji cells and HL60 cells respectively and enhanced the T cell mediated immunotherapy which provided dual-targeted ability in vitro .