Exploring the Limits of Overhauser Dynamic Nuclear Polarization (O-DNP) for Portable Magnetic Resonance Detection of Low γ Nuclei

Yoder, Jacob; Magnelind, Per E.; Espy, Michelle A.; Janicke, Michael T.

doi:10.1007/s00723-018-1014-1

Cited by 7 publications

(4 citation statements)

References 23 publications

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“…With NMR detection at the same field the challenge is to obtain enough spectral resolution, especially for proton spins. Recently it was shown that with improved magnetic field homogeneity and low paramagnetic concentrations line widths less than 4 Hz could be achieved at 0.3 T. 171 Experimental setups also exist for ultralow magnetic fields for imaging applications, 172 for detection of low-γ nuclei, 173 monitoring of flow reactions 174 or for magnetometry. 175 Recently, also a miniaturized setup working at 0.5 T magnetic field was described for microfluidic chip applications.…”

Section: Practical Aspectsmentioning

confidence: 99%

Spin Hyperpolarization in Modern Magnetic Resonance

et al. 2023

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Magnetic resonance techniques are successfully utilized in a broad range of scientific disciplines and in various practical applications, with medical magnetic resonance imaging being the most widely known example. Currently, both fundamental and applied magnetic resonance are enjoying a major boost owing to the rapidly developing field of spin hyperpolarization. Hyperpolarization techniques are able to enhance signal intensities in magnetic resonance by several orders of magnitude, and thus to largely overcome its major disadvantage of relatively low sensitivity. This provides new impetus for existing applications of magnetic resonance and opens the gates to exciting new possibilities. In this review, we provide a unified picture of the many methods and techniques that fall under the umbrella term "hyperpolarization" but are currently seldom perceived as integral parts of the same field. Specifically, before delving into the individual techniques, we provide a detailed analysis of the underlying principles of spin hyperpolarization. We attempt to uncover and classify the origins of hyperpolarization, to establish its sources and the specific mechanisms that enable the flow of polarization from a source to the target spins. We then give a more detailed analysis of individual hyperpolarization techniques: the mechanisms by which they work, fundamental and technical requirements, characteristic applications, unresolved issues, and possible future directions. We are seeing a continuous growth of activity in the field of spin hyperpolarization, and we expect the field to flourish as new and improved hyperpolarization techniques are implemented. Some key areas for development are in prolonging polarization lifetimes, making hyperpolarization techniques more generally applicable to chemical/biological systems, reducing the technical and equipment requirements, and creating more efficient excitation and detection schemes. We hope this review will facilitate the sharing of knowledge between subfields within the broad topic of hyperpolarization, to help overcome existing challenges in magnetic resonance and enable novel applications.

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Section: Practical Aspectsmentioning

confidence: 99%

Spin Hyperpolarization in Modern Magnetic Resonance

et al. 2023

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“…Reciprocally, relaxometry profiles in the solution state can help to design ODNP material systems by predicting DNP enhancements. , Low-field NMR, which has particular applications in compact NMR and in vivo imaging, is another subfield in which gains of more than 100-fold may be obtained using DNP. Compact NMR can enable “on-field” measurements of low-concentration analytes, including hazardous substances and reaction intermediates. − Increasing the sensitivity of low-field magnetic resonance imaging would be highly beneficial for developing low-cost in vivo imaging instruments that do not require cryogens, which are increasingly scarce. , …”

Section: Applications Of Liquid-state Dnp Nmrmentioning

confidence: 99%

“…Maly et al have shown recently that it is possible to improve both sensitivity and resolution even at low fields by improving field homogeneity . The ability to conduct DNP NMR at low fields is also desirable for portable setups …”

Section: Instrumental Challenges and Outlook For Liquid-state Dnp Nmrmentioning

confidence: 99%

Challenges and Advances in the Application of Dynamic Nuclear Polarization to Liquid-State NMR Spectroscopy

Abhyankar

Szalai

2021

J. Phys. Chem. B

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Nuclear magnetic resonance (NMR) spectroscopy is a powerful method to study the molecular structure and dynamics of materials. The inherently low sensitivity of NMR spectroscopy is a consequence of low spin polarization. Hyperpolarization of a spin ensemble is defined as a population difference between spin states that far exceeds what is expected from the Boltzmann distribution for a given temperature. Dynamic nuclear polarization (DNP) can overcome the relatively low sensitivity of NMR spectroscopy by using a paramagnetic matrix to hyperpolarize a nuclear spin ensemble. Application of DNP to NMR can result in sensitivity gains of up to four orders of magnitude compared to NMR without DNP. Although DNP NMR is now more routinely utilized for solid-state (ss) NMR spectroscopy, it has not been exploited to the same degree for liquid-state samples. This Review will consider challenges and advances in the application of DNP NMR to liquid-state samples. The Review is organized into four sections: (i) mechanisms of DNP NMR relevant to hyperpolarization of liquid samples; (ii) applications of liquid-state DNP NMR; (iii) available detection schemes for liquid-state samples; and (iv) instrumental challenges and outlook for liquid-state DNP NMR.

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“…Currently, Overhauser DNP (ODNP) is increasingly used in combination with compact NMR instruments [ 20 , 21 , 22 , 23 , 24 ] because ODNP units are rather small and add only moderately to the weight and size of the overall NMR system. Compact NMR systems are mainly based on permanent magnets and allow a very flexible use of NMR spectroscopy because a dedicated laboratory infrastructure and cryogenic coolants are not needed.…”

Section: Introductionmentioning

confidence: 99%

Functionalized Controlled Porous Glasses for Producing Radical-Free Hyperpolarized Liquids by Overhauser DNP

et al. 2022

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Overhauser dynamic nuclear polarization (ODNP) can be used as a tool for NMR signal enhancement and happens on very short time scales. Therefore, ODNP is well suited for the measurement of fast-flowing samples, even in compact magnets, which is beneficial for the real-time monitoring of chemical reactions or processes. ODNP requires the presence of unpaired electrons in the sample, which is usually accomplished by the addition of stable radicals. However, radicals affect the nuclear relaxation times and can hamper the NMR detection. This is circumvented by immobilizing radicals in a packed bed allowing for the measurement of radical-free samples when using ex situ DNP techniques (DNP build-up and NMR detection happen at different places) and flow-induced separation of the hyperpolarized liquid from the radicals. Therefore, the synthesis of robust and chemically inert immobilized radical matrices is mandatory. In the present work, this is accomplished by immobilizing the radical glycidyloxy-tetramethylpiperidinyloxyl with a polyethyleneimine (PEI) linker on the surface of controlled porous glasses (CPG). Both the porosity of the CPGs and also the size of the PEI-linker were varied, resulting in a set of distinct radical matrices for continuous-flow ODNP. The study shows that CPGs with PEI-linkers provide robust, inert and efficient ODNP matrices.

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Exploring the Limits of Overhauser Dynamic Nuclear Polarization (O-DNP) for Portable Magnetic Resonance Detection of Low γ Nuclei

Cited by 7 publications

References 23 publications

Spin Hyperpolarization in Modern Magnetic Resonance

Spin Hyperpolarization in Modern Magnetic Resonance

Challenges and Advances in the Application of Dynamic Nuclear Polarization to Liquid-State NMR Spectroscopy

Functionalized Controlled Porous Glasses for Producing Radical-Free Hyperpolarized Liquids by Overhauser DNP

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