Multiple Ultrafast, Broadband 2D NMR Spectra of Hyperpolarized Natural Products

Giraudeau, Patrick; Shrot, Yoav; Frydman, Lucio

doi:10.1021/ja905096f

Cited by 106 publications

(106 citation statements)

References 20 publications

Supporting

Mentioning

102

Contrasting

Order By: Relevance

“…13 D-DNP has hardly been applied to complex mixtures of metabolites, 14 but only to a few wellchosen small molecules. [15][16][17][18] The detection of 2D spectra after D-DNP has been reported on such mixtures of small mole- † Electronic supplementary information (ESI) available: Details of sample preparation, D-DNP and NMR; additional experimental results. See…”

mentioning

confidence: 99%

Hyperpolarized NMR of plant and cancer cell extracts at natural abundance

Dumez

Milani

Vuichoud

et al. 2015

Analyst

Self Cite

103

View full text Add to dashboard Cite

Natural abundance 13 C NMR spectra of biological extracts are recorded in a single scan provided that the samples are hyperpolarized by dissolution dynamic nuclear polarization combined with cross polarization. Heteronuclear 2D correlation spectra of hyperpolarized breast cancer cell extracts can also be obtained in a single scan. Hyperpolarized NMR of extracts opens many perspectives for metabolomics.Lying at the interface of chemistry and biology, metabolomics is one of the youngest sprouts of the sprawling tree of "omic" sciences. The last decade has witnessed a growing interest in mapping metabolic pathways, in identifying new biomarkers, and in modeling metabolic fluxes. 1,2 Nuclear Magnetic Resonance (NMR) spectroscopy is a major analytical technique in this field, offering unambiguous information about the identity of metabolites and their time-dependent concentrations in complex samples such as biofluids, extracts and tissues. However, proton NMR spectra have a limited range of chemical shifts and often suffer from overlapping signals. Carbon-13, which has a larger chemical shift dispersion, can benefit from sensitive detectors 3 or from isotopic enrichment, 4 albeit at the cost of an enhanced complexity of the spectra due to 13 C-13 C couplings. Heteronuclear ( 1 H→ 13 C) correlation spectroscopy can in principle offer a satisfactory dispersion. 5,6 So far, 13 C NMR is not routinely used in metabolomic studies, but hyperpolarization by dissolution dynamic nuclear polarization (D-DNP) combined with cross polarization (CP) could boost its popularity in this field.Hyperpolarization techniques are capable of generating spin polarization levels that are about 50 000 times above Boltzmann equilibrium at room temperature. 7-9 Once prepared and transferred to a solution-state NMR spectrometer, the resulting magnetization can be exploited within a limited time-span that depends on the longitudinal relaxation time T 1 of the hyperpolarized nuclei. Among various methods for hyperpolarization, dynamic nuclear polarization (DNP) is least affected by the chemical substrate and sample preparation. 10 For solution-state NMR, particularly promising results can be obtained by dissolution DNP, where the sample to be analyzed is mixed with free radicals in a glass-forming solution, frozen to liquid helium temperatures, and hyperpolarized by irradiating in the vicinity of the electron spin resonance (ESR) of the unpaired electrons of the radicals. 11 Spins of 13 C nuclei may be polarized either directly or via cross-polarization from protons to 13 C. 12 Rapid melting and shuttling of the sample from the polarizer to a routine NMR spectrometer enables conventional solution-state NMR spectroscopy with a sensitivity that can be boosted by a factor of about 50 000. Most applications of D-DNP have been restricted to the injection of pure hyperpolarized 13 C-labeled molecules such as pyruvate into living organisms. 13 D-DNP has hardly been applied to complex mixtures of metabolites, 14 but only to a few wellchosen small molecules...

show abstract

mentioning

confidence: 99%

Hyperpolarized NMR of plant and cancer cell extracts at natural abundance

Dumez

Milani

Vuichoud

et al. 2015

Analyst

Self Cite

103

View full text Add to dashboard Cite

show abstract

“…This hyperpolarization, however, decays with the longitudinal relaxation time T 1 , and it cannot be preserved at the level of constancy normally demanded by conventional 2D NMR acquisitions. By contrast, ultrafast 2D techniques that rely on spatio-temporal encodings to monitor the indirect-domain evolution [15][16], have been shown capable of making full use of this hyperpolarization [17][18][19]. While spatio-temporal methods can deliver 2D NMR spectra in a single scan without a priori knowledge, they face a number of technical limitations.…”

Section: Introductionmentioning

confidence: 99%

HyperSPASM NMR: A new approach to single-shot 2D correlations on DNP-enhanced samples

Donovan

Frydman

2012

Journal of Magnetic Resonance

Self Cite

View full text Add to dashboard Cite

Dissolution DNP experiments are limited to a single or at most a few scan, before the nonBoltzmann magnetization has been. This makes it impractical to record 2D NMR data by conventional, t 1 -incremented schemes. Here a new approach termed HyperSPASM to establish 2D heteronuclear correlations in a single scan is reported, aimed at dealing with this kind of challenge. The HyperSPASM experiment relies on imposing an amplitude-modulation of the data by a single Δt 1 indirect-domain evolution time, and subsequently monitoring the imparted encoding on separate echo and the anti-echo pathway signals within a single continuous acquisition. This is implemented via the use of alternating, switching, coherence selection gradients. As a result of these manipulations the phase imparted by a heteronucleus over its indirect domain evolution can be accurately extracted, and 2D data unambiguously reconstructed with a single-shot excitation. The nature of this sequence makes the resulting experiment particularly well suited for the collecting indirectly-detected HSQC data on hyperpolarized samples. The potential of the ensuing "HyperSPASM" method is exemplified with natural-abundance hyperpolarized correlations on model systems.

show abstract

“…It can thus yield liquid signals that have been enhanced several orders of magnitude, opening up new, hitherto untapped opportunities that have been applied successfully in analytical NMR and preclinical MRI applications. (2)(3)(4)(5)(6)(7)(8) One drawback of this liquids-oriented ex situ DNP, relates to the sample dilution that is inherent to it. This method requires sufficient volume of hot solvent for both the sudden melting of the targeted pellet from its cryogenic environment to near room temperature conditions, as well as for rapidly transferring the resulting sample from the hyperpolarization to the NMR/MRI environs.…”

Section: Introductionmentioning

confidence: 99%

Dissolution DNP NMR with solvent mixtures: Substrate concentration and radical extraction

Harris

Bretschneider

Frydman

2011

Journal of Magnetic Resonance

Self Cite

View full text Add to dashboard Cite

Dynamic nuclear polarization (DNP) followed by sudden sample dissolution, is a topic of active investigation owing to the method's unique prospects for the delivery of NMR spectra and images with unprecedented sensitivity. This experiment achieves hyperpolarization by the combined effects of electron-nuclear irradiation and cryogenic operation; the exploitation of these states occurs following a sudden melting and flushing of the resulting pellet from its original environment into a conventional, liquid-state setting. This melting and flushing usually demands using the equivalent of a few milliliters of hot solvent, a procedure which although well suited for in vivo studies leads to an excessive sample volume when considering typical applications within analytical settings. The present study explores a way of reducing the ensuing dilution of the hyperpolarized analytes, by employing a combination of immiscible liquids for performing the melting and flushing. It is shown that suitable combinations of immiscible solvents -both in terms of their heat capacities and densities-allow one to melt the targeted cryogenic pellet and dissolve the hyperpolarized analytes in a fraction of the solvent hitherto required. By tailoring the resulting volume to the needs of a conventional 5mm NMR probe, a substantial sensitivity enhancement can be added to the hyperpolarization process. An extra benefit may arise from using radicals that preferentially dissolve in the immiscible organic phase, by way of a lengthening of the relaxation time of the investigated analytes. Examples of these principles are given, and further potential extensions of this approach are discussed.

show abstract

Multiple Ultrafast, Broadband 2D NMR Spectra of Hyperpolarized Natural Products

Cited by 106 publications

References 20 publications

Hyperpolarized NMR of plant and cancer cell extracts at natural abundance

Hyperpolarized NMR of plant and cancer cell extracts at natural abundance

HyperSPASM NMR: A new approach to single-shot 2D correlations on DNP-enhanced samples

Dissolution DNP NMR with solvent mixtures: Substrate concentration and radical extraction

Contact Info

Product

Resources

About