The effect of neighbor distance of magnetic nanoparticle clusters on magnetic resonance relaxation properties  

作　　者：Dan Wang Bingbing Lin Taipeng Shen Jun Wu Chunchao Xia Bin Song Hua Ai 

机构地区：[1]National Engineering Research Center for Biomaterials, Sichuan University [2]Department of Radiology, West China Hospital, Sichuan University

出　　处：《Science Bulletin》2016年第13期1023-1030,共8页科学通报（英文版）

基　　金：supported by the National Key Basic Research Program of China (2013CB933903);the National High Technology R&D Program of China (2012BAI23B08);the National Natural Science Foundation of China (20974065, 51173117 and 50830107)

摘　　要：Superparamagnetic iron oxide （SPIO） nanoparticle clusters are one unique form which can enhance magnetic relaxivity and improve the magnetic resonance imaging contrast at the same iron concentration, comparing to single SPIO nanoparticles. Controlling of cluster size and other structural parameters have drawn great interests in this field to further improve their magnetic properties. In this study, we investigated how the interparticle distance （also known as neighbor distance） of SP10 nanocrystals within clusters affect their magnetic relaxation behaviors. To adjust the neighbor distance, different amount of cholesterol （CHO） was chosen as model spacers embedded into SPIO nanocluster systems with the help of amphiphilic diblock copolymer poly（ethylene glyco）-polyester. Small- angle X-ray scattering was applied to quantify the neighbor distance of SPIO clusters. The results demonstrated that the averaged SPIO nanocrystal neighbor distance of nan- oclusters increased with higher amount of added CHO. Moreover, these SPIO nanocrystal clusters had the promi- nent magnetic relaxation properties. Simultaneously, con- trolling of SPIO nanocrystal neighbor distance can regulate the saturation magnetization （Ms） and magnetic resonance （MR） T2 relaxation of the aggregation, and ultimately obtain better MR contrast effects with decreased neighbor distance.Superparamagnetic iron oxide(SPIO) nanoparticle clusters are one unique form which can enhance magnetic relaxivity and improve the magnetic resonance imaging contrast at the same iron concentration, comparing to single SPIO nanoparticles. Controlling of cluster size and other structural parameters have drawn great interests in this field to further improve their magnetic properties. In this study, we investigated how the interparticle distance(also known as neighbor distance) of SPIO nanocrystals within clusters affect their magnetic relaxation behaviors.To adjust the neighbor distance, different amount of cholesterol(CHO) was chosen as model spacers embedded into SPIO nanocluster systems with the help of amphiphilic diblock copolymer poly(ethylene glyco)-polyester. Smallangle X-ray scattering was applied to quantify the neighbor distance of SPIO clusters. The results demonstrated that the averaged SPIO nanocrystal neighbor distance of nanoclusters increased with higher amount of added CHO.Moreover, these SPIO nanocrystal clusters had the prominent magnetic relaxation properties. Simultaneously, controlling of SPIO nanocrystal neighbor distance can regulate the saturation magnetization(Ms) and magnetic resonance(MR) T2 relaxation of the aggregation, and ultimately obtain better MR contrast effects with decreased neighbor distance.

关 键 词：Iron oxide nanoparticle CLUSTERS Neighbor distance Magnetic properties T2relaxation 

分 类 号：O614.811[理学—无机化学] TB383.1[理学—化学]