Magnetic Nanobeads as Potential Contrast Agents for Magnetic Resonance Imaging

作者：Pablico Lansigan Michele H; Hickling William J; Japp Emily A; Rodriguez Olga C; Ghosh Anup; Albanese Chris; Nishida Maki; Van Keuren Edward; Fricke Stanley; Dollahon Norman; Stoll Sarah L^*

来源：ACS Nano, 2013, 7(10): 9040-9048.

DOI：10.1021/nn403647t

• miniemulsion nanobeads
• manganese oxo clusters
• contrast agents

Metal-oxo clusters have been used as building blocks to form hybrid nanomaterials and evaluated as potential MRI contrast agents. We have synthesized a biocompatible copolymer based on a water stable, nontoxic, mixed-metal-oxo cluster, Mn8Fe4O12(L)(16)(H2O)(4), where L is acetate or vinyl benzoic acid, and styrene. The cluster alone was screened by NMR for relaxivity and was found to be a promising T-2 contrast agent, with r(1) = 2.3 mM(-1) s(-1) and r(2) = 29.5 mM(-1) s(-1). Initial cell studies on two human prostate cancer cell lines, DU-145 and LNCap, reveal that the cluster has low cytotoxicity and may be potentially used in vivo. The metal-oxo cluster Mn8Fe4(VBA)(16) (VBA = vinyl benzoic acid) can be copolymerized with styrene under miniemulsion conditions. Miniemulsion allows for the formation of nanometer-sized paramagnetic beads (similar to 80 nm diameter), which were also evaluated as a contrast agent for MRI. These highly monodispersed, hybrid nanoparticles have enhanced properties, with the option for surface functionalization, making them a promising tool for biomedicine. Interestingly, both relaxivity measurements and MRI studies show that embedding the Mn8Fe4 core within a polymer matrix decreases r(2) effects with little effect on r(1), resulting in a positive T-1 contrast enhancement.

• 出版日期2013-10