In order to form the hydrophilic nanoparticles

the oleylamine ligand of oil-soluble iron oxide nanoparticles(IONPs) were ligand -exchanged with the amine groups of poly(amidoamine) dendrimers.Then the targeting molecules 5-hydroxytryptamine (5-HT) which can target myeloperoxidase in the atherosclerotic plaque were grafted on the dendritic polymer coating of nanoparticles.Finally

a targeted contrast imaging system (poly(amidoamine) dendrimers coat IONPs-graft-PEG-graft-5-HT

5-HT-PEG-G3.0@IONPs) which can target to atherosclerotic plaque and image for magnetic resonance imaging was achieved.Structure of all the samples were characterized by FTIR which could confirm that the products were successfully prepared.The sizes of particles were tested by dynamic light scattering (DLS) and also observed under transmission electron microscope (TEM).According to the tests

the nanoparticles showed a spherical and monodispersed structure

and DLS result showed that the diameters of 5-HT-PEG-G3.0@IONPs were about 31 nm and the TEM result was about 10 nm

respectively.The standard curve of 5-HT was portrayed based on the characteristic absorption peak at 276 nm in the UV-Vis test.Then the amount of 5-HT grafted on the final products was defined and the content of 5-HT was 6.19 g/mg.The results of thermogravimetric analysis (TGA) showed that about 2 wt% iron oxide was in the nanoparticles

and vibrating sample magnetometer (VSM) revealed the superparamagnetism of 5-HT-PEG-G3.0@IONPs nanoparticles

and the saturation magnetization was 1.47 Am2/kg.