Law Justin J, Guven Adem, Wilson Lon J
Department of Chemistry, Richard E. Smalley Center for Nanoscale Science and Technology, MS-60, Rice University, PO Box 1892, Houston, TX, 77251-1892, USA.
Contrast Media Mol Imaging. 2014 Nov-Dec;9(6):409-12. doi: 10.1002/cmmi.1603. Epub 2014 Apr 25.
Ultrashort single-walled carbon nanotubes loaded with gadolinium ions (gadonanotubes) have been previously shown to exhibit extremely high T1 -weighted relaxivities (>100 mm(-1) s(-1) ). To further examine the effect of nanoconfinement on the relaxivity of gadolinium-based contrast agents for magnetic resonance imaging, a series of ultrashort single-walled carbon nanotube (US-tube) materials internally loaded with gadolinium chelates have been prepared and studied. US-tubes were loaded with Gd(acac)3 · 2H2 O, Gd(hfac)3 · 2H2 O, and Gd(thd)3 (acac = acetylacetone, hfac = hexafluoroacetylacetone, thd = tetramethylheptanedione). The longitudinal relaxivities of the prepared materials determined at 25°C in a 1.5 T field were 103 mm(-1) s(-1) for Gd(acac)3 · 2H2 O@US-tubes, 105 mm(-1) s(-1) for Gd(hfac)3 · 2H2 O@US-tubes and 26 mm(-1) s(-1) for Gd(thd)3 @US-tubes. Compared with the relaxivities obtained for the unloaded chelates (<10 mm(-1) s(-1) ) as well as accounting for the T1 reduction observed for the empty US-tubes, the boost in relaxivity for chelate-loaded US-tubes is attributed to confinement within the nanotube and depends on the number of coordinated water molecules.
先前已表明，负载钆离子的超短单壁碳纳米管（钆纳米管）具有极高的 T1 加权弛豫率（>100 mm(-1) s(-1)）。为了进一步研究纳米限域对用于磁共振成像的钆基造影剂弛豫率的影响，制备并研究了一系列内部负载钆螯合物的超短单壁碳纳米管（US 管）材料。US 管中负载了 Gd(acac)3 · 2H2O、Gd(hfac)3 · 2H2O 和 Gd(thd)3（acac = 乙酰丙酮，hfac = 六氟乙酰丙酮，thd = 四甲基庚二酮）。在 25°C 的 1.5 T 磁场中测定的制备材料的纵向弛豫率，Gd(acac)3 · 2H2O@US 管为 103 mm(-1) s(-1)，Gd(hfac)3 · 2H2O@US 管为 105 mm(-1) s(-1)，Gd(thd)3@US 管为 26 mm(-1) s(-1)。与未负载螯合物获得的弛豫率（<10 mm(-1) s(-1)）相比，以及考虑到空 US 管观察到的 T1 降低情况，负载螯合物的 US 管弛豫率的提高归因于纳米管内的限域作用，并且取决于配位水分子的数量。
