Enhanced Overhauser contrast in proton–electron double-resonance imaging of the formation of an alginate hydrogel

Portable X-band system for solution state dynamic nuclear polarization

“…The Overhauser effect has found applications in Overhauser enhanced magnetic resonance imaging (OMRI) [7][8][9][10][11][12], flow imaging by remotely enhanced liquids for imaging contrast (RELIC) [13], or determining local viscosities near a spin-labeled micelle from changes in the Overhauser enhancement (unpublished). The efficiency of the Overhauser effect decreases with the magnetic field [14], but it is still effective at 0.35 T where electron spin resonance occurs at X-band frequencies that are relatively easy to generate, amplify and detect [15].…”

High speed 3D overhauser‐enhanced MRI using combined b‐SSFP and compressed sensing

“…Imaging of free radicals has been used to investigate a number of important physiological processes such as the mapping of pO 2 , free radical distribution and metabolism , molecular imaging , and to monitor changes in local viscosity . Magnetic resonance imaging (MRI) is a powerful and noninvasive tool that provides excellent anatomical detail.…”

Dynamic Nuclear Polarization Enhanced Nuclear Magnetic Resonance and Electron Spin Resonance Studies of Hydration and Local Water Dynamics in Micelle and Vesicle Assemblies

“…So, it is straightforward to translate the DNP enhancement at infinite power (E max ) into Fs max and, for a wide range of conditions, into the pure coupling factor, F. The coupling factor for 1 H NMR enhancement of (not degassed tap) water through dissolved nitroxide spin labels at 0.35 T was determined to be around 0.22, which is expected to decrease in more viscous, and increase in less viscous, local environments. [42][43][44]49 So, for fluid dynamics studies of soft matter applications as presented here, the use of the DNP method is well justified as a unique analysis tool complementary to NMR relaxometry and ESR.…”

“…This makes the DNP-amplified 1 H NMR signal of solution samples predominantly sensitive to the translational fluid dynamics of water directly interacting with the spin label. The sensitivity of the Overhauser effect to diffusion has already been employed as a contrast mechanism to monitor gel formation. − However, there the DNP effect was neither fully quantified in terms of motional parameters nor employed in combination with ESR techniques by using site-specific spin labels to obtain localized molecular information and solvent dynamics. In this manner, DNP-amplified NMR analysis using spin labels is complementary to ESR line shape analysis of those spin labels, which directly provides the rotational (or some translational) diffusion rates of the spin-labeled molecular segment.…”