Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The search for new methods of cancer diagnosis is leading to the development of multimodal imaging agents that may be detected by techniques such as Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET). A new bimodal imaging agent has been prepared which can be used for dual mode detection of cancer by both MRI and PET imaging. The imaging agent consists of an azamacrocyclic ligand, 1,4-bis (2-pyridilmethyl)-1,4,7-triazacyclononane (DMP-TACN), linked to iron oxide nanoparticles through polyethylene glycol (PEG) chains (M_n ~ 600) that are attached to the nanoparticle surface by silanization. The azamacrocyclic ligands serve as complexing agents for radioactive copper (⁶⁴Cu) for PET imaging, while the iron oxide nanoparticles work both as a carrier and an imaging agent for MRI. The iron oxide nanoparticles have been synthesized by thermal decomposition from iron oleate. The functionalized nanoparticles have sizes ranging between 7–10 nm, as determined by TEM, whilst Nanoparticle Tracking Analysis (NTA) experiments suggest an average hydrodynamic diameter of 50 nm. ⁶⁴Cu labeling experiments revealed that the nanoparticles loaded with DMP-TACN have a labeling yield of around 10%. MRI experiments in rats showed the nanoparticles accumulate in the liver 15 min after intravenous administration. 64Cu labeling and breast tumor cell labeling studies are currently being performed using the new nanoparticles.