Physics Department, Ben-Gurion University of the Negev, 8410501, Be'er Sheva, Israel.
Ioffe Institute, St. Petersburg, 194021, Russia.
MAGMA. 2020 Dec;33(6):885-888. doi: 10.1007/s10334-020-00847-3. Epub 2020 Apr 28.
Detonation nanodiamonds (DND) with Gd ions directly grafted to the DND surface have recently demonstrated enhanced relaxivity for protons in aqueous suspensions. Herewith, the relaxivity measurements were done on a series of suspensions with the gadolinium content varied by changing number of Gd ions grafted per each DND particle whereas the DND content in each suspension was kept the same. Such an approach to vary the contrast agent content differs from that commonly used in the relaxivity measurements. In the common approach, contrast agents are directly dissolved/suspended in media. Aiming to test validity of the unconventional approach, in the present study we follow the common way of measurement relaxivity: using variable concentrations of carriers (DND particles) in aqueous suspension keeping the number of Gd ions per each carrier fixed.
H NMR relaxation measurements of aqueous suspensions of DND with Gd ions directly grafted to the DND surface were carried out at room temperature (293 K or 20 °C) in the external magnetic field B = 8.0 T.
Comparative study of two approaches for measuring relaxivity in suspensions containing DND as magnetic entities' carriers reveals complete identity of techniques in use.
最近研究表明，直接接枝在纳米爆轰金刚石（DND）表面的钆离子的爆震纳米金刚石（DND）使水悬浮液中的质子的弛豫率得到增强。在此，通过改变每个 DND 颗粒上接枝的 Gd 离子数量来改变 Gd 含量，同时保持每个悬浮液中的 DND 含量相同，从而对一系列悬浮液进行了弛豫率测量。这种改变对比剂含量的方法与弛豫率测量中常用的方法不同。在常见的方法中，对比剂直接溶解/悬浮在介质中。为了测试非传统方法的有效性，在本研究中，我们采用了常见的测量弛豫率的方法：在水悬浮液中使用不同浓度的载体（DND 颗粒），保持每个载体上的 Gd 离子数量不变。
在室温（293 K 或 20°C）下，在外部磁场 B=8.0 T 下，对直接接枝在 DND 表面的 Gd 离子的 DND 水悬浮液进行了 H NMR 弛豫测量。
对含有 DND 作为磁性实体载体的悬浮液中测量弛豫率的两种方法的比较研究表明，所用技术完全相同。
