The Relationship between NMR Chemical Shifts of Thermally Polarized and Hyperpolarized Y Complexes and Their Solution Structures.

Recently developed dynamic nuclear polarization (DNP) technology offers the potential of increasing the NMR sensitivity of even rare nuclei for biological imaging applications. Hyperpolarized Y is an ideal candidate because of its narrow NMR linewidth, favorable spin quantum number (I=1/2 ), and long longitudinal relaxation times (T ). Strong NMR signals were detected in hyperpolarized Y samples of a variety of yttrium complexes.

Development and performance of a 129-GHz dynamic nuclear polarizer in an ultra-wide bore superconducting magnet.

Objective: We sought to build a dynamic nuclear polarization system for operation at 4.6 T (129 GHz) and evaluate its efficiency in terms of (13)C polarization levels using free radicals that span a range of ESR linewidths.

Materials And Methods: A liquid helium cryostat was placed in a 4.

Europium(III) DOTA-tetraamide complexes as redox-active MRI sensors.

PARACEST redox sensors containing the NAD(+)/NADH mimic N-methylquinolinium moiety as a redox-active functional group have been designed and synthesized. The Eu(3+) complex with two quinolinium moieties was nearly completely CEST-silent in the oxidized form but was "turned on" upon reduction with β-NADH. The CEST effect of the Eu(3+) complex containing only one quinolinium group was much less redox-responsive but showed an unexpected sensitivity to pH in the physiologically relevant pH range.

DNP by thermal mixing under optimized conditions yields >60,000-fold enhancement of 89Y NMR signal.

Hyperpolarized (89)Y complexes are attractive NMR spectroscopy and MR imaging probes due to the exceptionally long spin-lattice relaxation time (T(1) ≈ 10 min) of the (89)Y nucleus. However, in vivo imaging of (89)Y has not yet been realized because of the low NMR signal enhancement levels previously achieved for this ultra low-γ(n) nucleus. Here, we report liquid-state (89)Y NMR signal enhancements over 60,000 times the thermal signal at 298 K in a 9.

Hyperpolarized 89Y complexes as pH sensitive NMR probes.

Hyperpolarization can increase the sensitivity of NMR/MRI experiments, but the primary limitation is the T(1) decay of magnetization. Due to its long T(1), the hyperpolarized (89)Y nucleus makes an excellent candidate as an in vivo spectroscopy/imaging probe. Here we report the (89)Y chemical shift dependence upon pH for two hyperpolarized (89)Y(III) complexes and demonstrate how such complexes can be used as sensitive spectroscopy/imaging agents to measure pH.