OBJECTIVETo prepare immunomagnetic nanoparticles (IMNs) for HER2/neu-targeted radioimmunotherapy with herceptin, a humanized anti-p185-HER-2/neu monoclonal antibody targeting the extracellular domain of HER-2/neu receptor.

METHODSThe magnetic nanoparticles were synthesized by partial reductive precipitation method and the surface of the particles was chemically modified using silane coupling agent. Herceptin and histidine were covalently linked to the amine group upon the silica-coated magnetic nanoparticles modified by N-[3-(trimethoxysilyl) propyl]-ethylenediamine using glutaraldehyde method to prepare the IMNs. The nanoparticles were evaluated by diffraction (XRD), scanning electron microscope (SEM) and X- ray energy spectrometry (EDS), and the immunoreactivity of IMN was determined.

RESULTSThe average diameter of the decanoic acid-coated Fe(3)O(4) nanoparticle was about 20 nm with a magnetic saturation of 65 emu/g. The surface amino group was 0.5 µmol/mg after modification with the amid functional group, and the mean size of Herceptin-loaded IMNs was about 60 nm. The IMN retained good immunoreactivity of Herceptin.

CONCLUSIONThe IMNs exhibit good properties for potential application in tumor targeting therapy using Herceptin against HER-2/nue proto-oncogene.