Toward Design of Magnetic Nanoparticle Clusters Stabilized by Biocompatible Diblock Copolymers for T2-Weighted MRI Contrast

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• 作者：Sharavanan Balasubramaniam ; Sanem Kayandan ; Yin-Nian Lin ; Deborah F. Kelly ; Michael J. House ; Robert C. Woodward ; Timothy G. St. Pierre ; Judy S. Riffle ; Richey M. Davis
• 刊名：Langmuir
• 出版年：2014
• 出版时间：February 18, 2014
• 年：2014
• 卷：30
• 期：6
• 页码：1580-1587
• 全文大小：356K
• ISSN：1520-5827

文摘

We report the fabrication of magnetic particles comprised of clusters of iron oxide nanoparticles, 7.4 nm mean diameter, stabilized by a biocompatible, amphiphilic diblock copolymer, poly(ethylene oxide-b-d,l-lactide). Particles with quantitative incorporation of up to 40 wt % iron oxide and hydrodynamic sizes in the range of 80鈥?70 nm were prepared. The particles consist of hydrophobically modified iron oxide nanoparticles within the core-forming polylactide block with the poly(ethylene oxide) forming a corona to afford aqueous dispersibility. The transverse relaxivities (r₂) increased with average particle size and exceeded 200 s^鈥? mM Fe^鈥? at 1.4 T and 37 掳C for iron oxide loadings above 30 wt %. These experimental relaxivities typically agreed to within 15% with the values predicted using analytical models of transverse relaxivity and cluster (particle core) size distributions derived from cryo-TEM measurements. Our results show that the theoretical models can be used for the rational design of biocompatible MRI contrast agents with tailored compositions and size distributions.