新型NaGdF4纳米造影剂的制备及性能

Preparation and Properties of Novel NaGdF4 Nanoscale Contrast Agent

采用可逆加成-断裂链转移聚合(RAFT)方法,聚合聚乙二醇甲醚甲基丙烯酸酯(OEGMA)和丙烯酸(AA),得到线型嵌段共聚物P(AAb-OEGMA)(PAO)。采用不同分子量的PAO对疏水性NaGdF4纳米颗粒进行亲水性修饰,得到单分散和纳米聚集体形貌的PAO-NaGdF4水分散液(PAO-NaGdF4-NPs,PAO-NaGdF4-Cluster),二者结构稳定且无钆离子的泄漏,弛豫率是商用Gd-DTPA造影剂的1.5~2倍,作为新型纳米造影剂具有临床转化的前景。

In order to improve contrast of magnetic resonance imaging(MRI),contrast agents have been used and developed in recent years.However,traditional gadolinium(Gd)-based contrast agents have low relaxation and high toxicity.So nanoscale magnetic resonance contrast agents have attracted wide attention due to their stable structure and high relaxation rate.Herein,we synthesized a new kind of nanoscale contrast agent used di-block copolymer P(AA-b-OEGMA)modified NaGdF4 nanocrystalwith high r1 relaxivity and stable structure.The linear block copolymer P(AA-b-OEGMA)(PAO)was obtained by means of reversible addition and broken chain transfer polymerization(RAFT).PAO-NaGdF4 aqueous dispersions(PAO-NaGdF4-NPs,PAO-NaGdF4-Cluster)were prepared by ligand exchange using PAO with different molecular weights.With stable structure and no leakage of gadolinium ions,the relaxation rate of the two agents is 1.5~2 times that of commercial Gd-DTPA contrast agent,which has the great potential of clinical transformation as new nanoscale contrast agents.