The Study Of High Relaxivity Magnetic Resonance Imaging Contrast Agent Based On Diethylenetriamine

Magnetic Resonance Imaging (MRI) is an important clinical diagnostic method. Gd(â…¢)-based T1 weighted contrast agents are the most widely used in clinic. Many researches are focused on designing high sensitive contrast agents for high magnetic field MRI imaging today. Previous results of diethyltriamine based ligands coordinate with Gd(â…¢) ion show that the coordination constants (logKGdL) are high enough to decrease the concentration of free Gd(â…¢) ion for safety in vivo applications. Metallosurfactants represent a class of transition metal-containing surfactants. Moreover, the special structure gifts two properties. On one hand, they are capable of decreasing the surface tension and aggregating at the interfaces similar to traditional surfactants. On the other hand, they have been recently found important potential applications in diverse areas such as magnetic resonance imaging, templating of mesoporous materials, thin-film optoelectronics, interfacial photophysics and homogeneous catalysis. We prepared colloids through emulsion polymerization with amphiphilic Gd(â…¢)-metallosurfactants based on diethylenetriamine. The attachment to polymer nanoparticles increase the rotational correlation time (Ï„R) of Gd(â…¢) complexes to give high relaxivity. NMR and MS are used to characterize the structures of ligands and complexes; ICP-AES is used to determine the Gd(â…¢) concentrations; and DLS, SEM, TEM are applied to observe the size, size distribution and morphology of the colloids. The most important property-relaxivity of these colloids is obtained through MRI.