Bifunctional Mn ₃ O ₄ And Fe ₃ O _{Synthetic 4} And Magnetic Nanoparticles In CT / MRI Imaging Applications

Amino-functionalized Fe₃O₄and Mn₃O₄namoparticles （Fe₃O₄-NH₂andMn₃O₄-NH₂） were prepared under the premise of6-（1,3-dioxo isoindoline） hexanoicacid as precursor. The amino density of the NPs reached10^-5mol/g, and the averagediameter of Fe₃O₄-NH₂and Mn₃O₄-NH₂NPs are respectively4.5±0.7and3.6±0.6nm. Then,2,3,5-triiodobenzoicacid with function of CT imaging, were linked withFe₃O₄-NH₂and Mn₃O₄-NH₂NPs for the reaction between the acyl chloride and amino,obtaining the formed Fe₃O₄-CT and Mn₃O₄-CT NPs which have the dual function of CTand MRI. The dual functional NPs have good water-solubility, biocompatibility andlow toxicity. The T1relaxivities （r1） of Mn₃O₄-NH₂and Mn₃O₄-CT NPs are1.8,2.9mM^-1· s^-1, and the T2relaxivities （r2） of the formed Fe₃O₄-NH₂and Fe₃O₄-CT NPs is15.5,31.9mM^-1· s^-1in a magnetic field of0.5T. Fitting line with differentconcentration of several sample and CT value obtained from the CT imaging test, wedraw a conclusion: for Fe₃O₄-CT NPs, the slope of the line reached10.5mM^-1· HU, forMn₃O₄-CT NPs, the slope of the line reached11.0mM^-1· HU, both of them show acertain degree of CT angiography effect. It follows that Fe₃O₄-CT and Mn₃O₄-CT NPshave the potential application ability on CT and MRI imaging.Furthermore, Mn₃O₄-NH₂NPs were modified with the dendrimerG3PAMAM using glutaraldehyde in order to increase the amino group on the surfaceof the Mn₃O₄NPs.The formed Mn₃O₄-G3PAMAM-CT NPs show more effective CTangiography effect, the slope of the line reached22.8mM^-1· HU, the longitudinalrelaxation rate （r1） decresed to1.0mM^-1· s^-1, more smaller than Mn₃O₄-NH₂andMn₃O₄-CT due to the dendrimer G3PAMAM.