CONSTRUCTION OF A FLEXIBLE HYPERPOLARIZATION SYSTEM

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. A flexible dynamic nuclear polarization instrument is under construction at the RR. It is planned to be a more flexible instrument than the commercially-available Oxford HyperSense DNP system. Further, the terms and conditions of purchase of the HyperSense prohibit in vivo experiments. With an eye towards potential large mammal in vivo applications, the system is being designed around a larger sample container that will hold approximately twice the amount of sample as the HyperSense sample cup. The DNP system will be based on a cryostat designed in collaboration with Mark Conradi of Washington University placed in a Bruker 15cm bore magnet energized to a field of ~4.6 Tesla. Recent results have demonstrated that incremental increases in field strength can yield dramatically higher nuclear polarizations.(1,2) With this in mind, we have designed the new system to operate at an ESR frequency of ~129 GHz. Furthermore, the extra space available in the large bore magnet should allow the incorporation of a double resonance probe for 1H and either 13C or 89Y. Cross-polarization solid state NMR pulse sequences can then be used to transfer polarization from high gamma protons, which polarize much more quickly under DNP than lower gamma species, to the detection nucleus.(3) References for construction of a polarizer: 1. Jannin S, Comment A, Kurdzesau F, Konter JA, Hautle P, van den Brandt B, van der Klink JJ. A 140 GHz prepolarizer for dissolution dynamic nuclear polarization. The Journal of Chemical Physics 2008;128(24):241102-241104. 2. J¿hannesson H, Macholl S, Ardenkjaer-Larsen JH. Dynamic Nuclear Polarization of [1-13C]pyruvic acid at 4.6 tesla. Journal of Magnetic Resonance 2009;197(2):167-175. 3. Maly T, Debelouchina GT, Bajaj VS, Kan-Nian H, Chan-Gyu J, Mak-Jurkauskas ML, Sirigiri JR, van der Wel PCA, Herzfeld J, Temkin RJ, Griffin RG. Dynamic nuclear polarization at high magnetic fields. Journal of Chemical Physics 2008;128(5):N.PAG.