中文摘要：

合成了一种新型可聚合型含钆单体,在温敏单体N-异丙基丙烯酰胺存在下,采用无皂乳液聚合法一步制备了含钆温度敏感的高分子微球.透射电子显微镜测试表明微球呈单分散性;动态光散射测试表明高分子微球的平均水合粒径约260 nm,呈现很窄的粒径分布;当温度从25℃升到45℃时,其粒径减小约60 nm,表明含钆高分子微球具有较好的温度敏感性.体外MRI测试表明,所得高分子微球的体外弛豫率为8.01（mmol/L）^-1S^-1（3 T）,能有效的增强MRI信号,具有优良的MRI造影功能.上述结果表明,所得微球作为一种多功能MRI造影剂,在生物医学领域极具应用前景.

英文摘要：

For the sake of simplifying the processes of synthesizing polymer modified gadolinium-based MRI contrast agents,and preparing gadolinium-containing and temperature-sensitive polymeric microsphere in a facile way,we choose soap-free emulsion polymerization as a synthetic method. Temperature-sensitive polymeric microspheres are prepared by soap-free emulsion polymerization in the presence of temperature-sensitive monomer N-isopropylacrylamide and polymerizable gadolinium monomer. Transmission electron microscope tests show the monodispersity of the polymeric microspheres. The dynamic light scattering tests indicate that the hydrodynamic diameters of the polymeric microspheres are about 260 nm with narrow size distribution,the hydrodynamic diameters of the polymeric microspheres decrease by about 60 nm when temperature increases from 25 ℃ to 45 ℃,and the swelling ratio（ defined as（ Dh,25 ℃/ Dh,45 ℃）^3） is 2. 06,indicating the good temperature-sensitive property of the polymeric microsphere. The contents of gadolinium in polymeric microsphere emulsion（ solid content 1%） are 1 mg / L. In vitro T1-weighted ralaxivity（ r1） at 3. 0 T is 8. 01（ mmol/L）^-1S^-1,which is much higher than that of clinical gadolinium chelate（ Gd-DTPA）. The polymeric microspheres show great prospects in pre-clinical MR imaging.