Lumata, Lloyd L.

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Lloyd Lumata is an Associate Professor of Physics. His expertise is in biomedical physics and his research interests include:

  • The application of hyperpolarized magnetic resonance biosensors in biomedical NMR spectroscopy and imaging (MRI)
  • Dynamic nuclear polarization (DNP)–a combination of cryogenics, NMR and EPR technologies–to amplify magnetic resonance signals by several thousand-fold
  • Exploration of new hyperpolarized reporter molecules to improve medical diagnostics of cancer and other diseases via high resolution NMR spectroscopy and MRI

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Now showing 1 - 4 of 4
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    Supramolecular and Biomacromolecular Enhancement of Metal-Free Magnetic Resonance Imaging Contrast Agents
    (Royal Society of Chemistry) Lee, Hamilton; Shahrivarkevishah, Arezoo; Lumata, Jenica L.; Luzuriaga, Michael A.; Hagge, Laurel M.; Benjamin, Candace E.; Brohlin, Olivia R.; Parish, Christopher R.; Firouzi, Hamid R.; Nielsen, Stephen O.; Lumata, Lloyd L.; Gassensmith, Jeremiah J.; 0000-0003-2176-925X (Hamilton, L); 0000-0002-5420-1954 (Shahrivarkevishah, A); 0000-0002-4650-3768 (Lumata, JL)); 0000-0001-6128-8800 (Luzuriaga, MA); 0000-0003-1064-6991 (Hagge, LM); 0000-0002-9211-718X (Benjamin, CE); 0000-0003-3226-6711 (Brohlin, OR); 0000-0003-4537-5992 (Firouzi, HR); 0000-0003-3390-3313 (Nielsen, SO); 0000-0002-3647-3753 (Lumata, LL); 0000-0001-6400-8106 (Gassensmith, JJ); Lee, Hamilton; Shahrivarkevishah, Arezoo; Lumata, Jenica L.; Luzuriaga, Michael A.; Hagge, Laurel M.; Benjamin, Candace E.; Brohlin, Olivia R.; Parish, Christopher R.; Firouzi, Hamid R.; Nielsen, Stephen O.; Lumata, Lloyd L.; Gassensmith, Jeremiah J.
    Many contrast agents for magnetic resonance imaging are based on gadolinium, however side effects limit their use in some patients. Organic radical contrast agents (ORCAs) are potential alternatives, but are reduced rapidly in physiological conditions and have low relaxivities as single molecule contrast agents. Herein, we use a supramolecular strategy where cucurbit[8]uril binds with nanomolar affinities to ORCAs and protects them against biological reductants to create a stable radical in vivo. We further overcame the weak contrast by conjugating this complex on the surface of a self-assembled biomacromolecule derived from the tobacco mosaic virus.
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    Influence of ¹³C Isotopic Labeling Location on Dynamic Nuclear Polarization of Acetate
    (Amer Chemical Soc, 2017-05-19) Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Kovacs, Zoltan; Lumata, Lloyd L.; Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Lumata, Lloyd L.
    Dynamic nuclear polarization (DNP) via the dissolution method has alleviated the insensitivity problem in liquid-state nuclear magnetic resonance (NMR) spectroscopy by amplifying the signals by several thousand-fold. This NMR signal amplification process emanates from the microwave-mediated transfer of high electron spin alignment to the nuclear spins at high magnetic field and cryogenic temperature. Since the interplay between the electrons and nuclei is crucial, the chemical composition of a DNP sample such as the type of free radical used, glassing solvents, or the nature of the target nuclei can significantly affect the NMR signal enhancement levels that can be attained with DNP. Herein, we have investigated the influence of ¹³C isotopic labeling location on the DNP of a model ¹³C compound, sodium acetate, at 3.35 T and 1.4 K using the narrow electron spin resonance (ESR) line width free radical trityl OX063. Our results show that the carboxyl ¹³C spins yielded about twice the polarization produced in methyl ¹³C spins. Deuteration of the methyl ¹³C group, while proven beneficial in the liquid-state, did not produce an improvement in the ¹³C polarization level at cryogenic conditions. In fact, a slight reduction of the solid-state ¹³C polarization was observed when ²H spins are present in the methyl group. Furthermore, our data reveal that there is a close correlation between the solid-state ¹³C T₁ relaxation times of these samples and the relative ¹³C polarization levels. The overall results suggest the achievable solid-state polarization of ¹³C acetate is directly affected by the location of the ¹³C isotopic labeling via the possible interplay of nuclear relaxation leakage factor and cross-talks between nuclear Zeeman reservoirs in DNP.
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    Influence of Dy³⁺ and Tb³⁺ Doping on ¹³C Dynamic Nuclear Polarization
    (American Institute of Physics Inc, 2017-01-03) Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Fidelino, L.; Khemtong, C.; Hayati, Z.; Song, L.; Martins, Andr©; Sherry, A. Dean; Lumata, Lloyd L.; Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Martins, Andr©; Sherry, A. Dean; Lumata, Lloyd
    Dynamic nuclear polarization (DNP) is a technique that uses a microwave-driven transfer of high spin alignment from electrons to nuclear spins. This is most effective at low temperature and high magnetic field, and with the invention of the dissolution method, the amplified nuclear magnetic resonance (NMR) signals in the frozen state in DNP can be harnessed in the liquid-state at physiologically acceptable temperature for in vitro and in vivo metabolic studies. A current optimization practice in dissolution DNP is to dope the sample with trace amounts of lanthanides such as Gd3+ or Ho3+, which further improves the polarization. While Gd³⁺ and Ho³⁺ have been optimized for use in dissolution DNP, other lanthanides have not been exhaustively studied for use in ¹³C DNP applications. In this work, two additional lanthanides with relatively high magnetic moments, Dy³⁺ and Tb³⁺, were extensively optimized and tested as doping additives for ¹³C DNP at 3.35 T and 1.2 K. We have found that both of these lanthanides are also beneficial additives, to a varying degree, for ¹³C DNP. The optimal concentrations of Dy³⁺ (1.5 mM) and Tb³⁺ (0.25 mM) for ¹³C DNP were found to be less than that of Gd³⁺ (2 mM). W-band electron paramagnetic resonance shows that these enhancements due to Dy³⁺ and Tb³⁺ doping are accompanied by shortening of electron T₁ of trityl OX063 free radical. Furthermore, when dissolution was employed, Tb³⁺-doped samples were found to have similar liquid-state ¹³C NMR signal enhancements compared to samples doped with Gd³⁺, and both Tb³⁺ and Dy³⁺ had a negligible liquid-state nuclear T₁ shortening effect which contrasts with the significant reduction in T₁ when using Gd³⁺. Our results show that Dy³⁺ doping and Tb³⁺ doping have a beneficial impact on ¹³C DNP both in the solid and liquid states, and that Tb³⁺ in particular could be used as a potential alternative to Gd³⁺ in ¹³C dissolution DNP experiments.
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    The Effect of Glassing Solvent Deuteration and Gd³⁺ Doping on ¹³C DNP at 5 T
    (Royal Society of Chemistry, 2016-04-14) Kiswandhi, Andhika; Lama, Bimala; Niedbalski, Peter; Goderya, Mudrekh; Long, J.; Lumata, Lloyd L.; 0000-0002-3647-3753 (Lumata, LL); Kiswandhi, Andhika; Lama, Bimala; Niedbalski, Peter; Goderya, Mudrekh; Lumata, Lloyd L.
    We report the influence of glassing solvent deuteration and Gd³⁺ doping on ¹³C dynamic nuclear polarization (DNP) nuclear magnetic resonance (NMR) performed on [1-¹³C] sodium acetate at B₀ = 5 T and 1.2 K. Our data reveal that at 5 T, glassing solvent deuteration still results in a 40% improvement of the ¹³C DNP signal when a large electron spin resonance (ESR) linewidth 4-oxo-TEMPO free radical is used, but results in a 60% decrease of the DNP signal in the case of a sample doped with small ESR linewidth trityl OX063. An addition of a trace amount of the Gd³⁺ complex Gd-HP-DO3A led to a negligible slight decrease on the ¹³C polarization TEMPO-doped sample, but is still relatively beneficial for the trityl-doped sample with 30% improvement of the DNP-enhanced ¹³C polarization. These findings indicate that while these DNP optimization steps are still valid at 5 T, the effects are not as pronounced as observed in ¹³C DNP at B₀ = 3.35 T. These DNP results at 5 T are discussed thermodynamically within the framework of the thermal mixing model of DNP.

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