We report on the first 1H NMR relaxation and magnetic resonance imaging (MRI) study of aqueous suspensions of detonation nanodiamond (DND) grafted by Gd­(III) ions. In contrast to Gd­(III)–ND conjugates implemented via organic species, Gd­(III) ions were directly grafted to the surface of DND particles. Such Gd­(III)-grafted DND particles significantly shorten spin–lattice (T 1) and spin–spin (T 2) relaxation times of water protons providing relaxivities of r 1 = 33.4 and r 2 = 332 mM–1 s–1, which considerably exceed most of those reported in the literature. It makes the Gd­(III)-grafted DND complexes attractive for use as novel MRI contrast agents.

No abstract

Purpose: Testing the potential use of saline suspension of polyvinylpyrrolidone (PVP)-coated gadolinium(Gd)-grafted detonation nanodiamonds (DND) as a novel contrast agent in MRI. Methods: Stable saline suspensions of highly purified de-agglomerated Gd-grafted DND particles coated by a PVP protective shell were prepared. T 1 and T 2 proton relaxivities of the suspensions with varying gadolinium concentration were measured at 8 Tesla. A series of ex vivo (phantom) and in vivo dynamic scans were obtained in 3 Tesla MRI using PVP-coated Gd-grafted DND and gadoterate meglumin in equal concentrations of gadolinium, and then T 1 -weighted hyperintensity was compared. Results: The proton relaxivities of PVP-coated Gd-grafted DND were found to be r 1 = 15.9 ± 0.8 s −1 mM −1 and r 2 = 262 ± 15 s −1 mM −1 , respectively, which are somewhat less than those for uncoated Gd-grafted DND but still high enough. Ex vivo MRI evaluation of PVP-coated Gd-grafted DND results with a dose-dependent T 1 -weighted hyperintensity with a significant advantage over the same for gadoterate meglumin. The same was found when the 2 contrast agents were tested in vivo. Conclusion:The novel MRI contrast agent -saline suspensions of PVP-coated Gd-grafted DND -provides significantly higher signal intensities than the common tracer gadoterate meglumin, therefore increasing its potential for a safer use in clinics.

No abstract

No abstract