Synthesis of protoporphyrin coated superparamagnetic iron oxide nanoparticles via dopamine anchor

Dopamine conjugated protoporphyrin, PPD, was prepared by the coupling reaction of protoporphyrin IX and dopamine in the presence of dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) in DMF. The crude product was washed with ethanol–cyclohexane (1:1) mixture to remove dicyclohexylurea (DCU). Previously prepared Fe3O4 nanoparticles were coated with PPD (sub-7 nm monosize) by sonication in the methanol. The porphyrin coated Fe3O4 nanoparticles, PPDNP were separated by permanent magnet. The microstructure and magnetic properties of magnetic nanoparticles were characterized by XRD, TEM, FT-IR, and VSM. It is found that the nanoparticles have high crystallinity with distinct lattices and the magnetic measurements reveal their well-defined superparamagnetic behavior at room temperature.