Nanosized cancer cell-targeted polymeric immunomicelles loaded with superparamagnetic iron oxide nanoparticles

Stable 30–50 nm polymeric polyethylene glycol–phosphatidylethanolamine (PEG–PE)-based micelles entrapping superparamagnetic iron oxide nanoparticles (SPION) have been prepared. At similar concentrations of SPION, the SPION-micelles had significantly better magnetic resonance imaging (MRI) T2 relaxation signal compared to ‘plain’ SPION. Freeze-fracture electron microscopy confirmed SPION entrapment in the lipid core of the PEG–PE micelles. To enhance the targeting capability of these micelles, their surface was modified with the cancer cell-specific anti-nucleosome monoclonal antibody 2C5 (mAb 2C5). Such mAb 2C5-SPION immunomicelles demonstrated specific binding with cancer cells in vitro and were able to bring more SPION to the cancer cells thus demonstrating the potential to be used as targeted MRI contrast agents for tumor imaging.