A new and innovative electron paramagnetic resonance (EPR) methodology will be developed for in vivo spectroscopy, imaging and biomedical research. A partnership of engineers, research scientists, clinicians, and industry propose to design and build rapid-scan EPR systems operating at 250 MHz and at L-band (ca. 1.2 GHz). The emphasis is on careful engineering of the spectrometer systems, including magnet, scan coils, resonator, and data acquisition to optimize physiological EPR signal acquisition for in vivo spectroscopy and imaging at the low RF frequencies that are accepted as the best compromises between penetration depth and signal to noise for in vivo animal studies. Rapid-scan EPR encompasses the regime in which the magnetic field sweep is fast relative to relaxation times, which is a newly developed intermediate regime between CW and pulsed EPR. Direct-detection rapid-scan EPR signals provide the absorption lineshape directly, reveal electron spin relaxation times without requiring high incident power, and provide accurate relative amplitudes of peaks in rapidly decaying signals.
The Specific Aims are: (1) Build a dedicated rapid-scan spectrometer at L-band (ca. 1.2 GHz) with scan rates optimized for biomedical, in vivo, and imaging experiments. (2) At 250 MHz build improved resonators, rapid-scan coils and drivers, and optimize the rapid-scan bridge. (3) Build a 250 MHz rapid-scan bridge, resonator, and magnetic field scan coil unit at the University of Denver and install it at the University of Chicago Center for In Vivo Imaging of Physiology, where it will be used to image oxygen concentrations in animal tumors. The benefits of traditional CW imaging, pulsed EPR imaging, and rapid-scan imaging for oximetry and oncology will be compared. (4) Design, build and test hardware/software systems for acquisition of the rapid-scan signal and post-processing of spectral information that will be used at 250 MHz and at L-band.
|Elajaili, Hanan; Biller, Joshua R; Rosen, Gerald M et al. (2015) Imaging disulfide dinitroxides at 250 MHz to monitor thiol redox status. J Magn Reson 260:77-82|
|Elajaili, Hanan B; Biller, Joshua R; Tseitlin, Mark et al. (2015) Electron spin relaxation times and rapid scan EPR imaging of pH-sensitive amino-substituted trityl radicals. Magn Reson Chem 53:280-4|
|Biller, Joshua R; Tseitlin, Mark; Mitchell, Deborah G et al. (2015) Improved sensitivity for imaging spin trapped hydroxyl radical at 250 MHz. Chemphyschem 16:528-31|
|Eaton, Sandra S; Eaton, Gareth R (2015) Rapid-Scan EPR of Nitroxide Spin Labels and Semiquinones. Methods Enzymol 563:3-21|
|Tseitlin, Mark; Yu, Zhelin; Quine, Richard W et al. (2014) Digitally generated excitation and near-baseband quadrature detection of rapid scan EPR signals. J Magn Reson 249:126-134|
|Biller, Joshua R; Tseitlin, Mark; Quine, Richard W et al. (2014) Imaging of nitroxides at 250MHz using rapid-scan electron paramagnetic resonance. J Magn Reson 242:162-8|
|Tseitlin, Mark; Biller, Joshua R; Elajaili, Hanan et al. (2014) New spectral-spatial imaging algorithm for full EPR spectra of multiline nitroxides and pH sensitive trityl radicals. J Magn Reson 245:150-5|
|Yu, Zhelin; Quine, Richard W; Rinard, George A et al. (2014) Rapid-scan EPR of immobilized nitroxides. J Magn Reson 247:67-71|
|Mitchell, Deborah G; Rosen, Gerald M; Tseitlin, Mark et al. (2013) Use of rapid-scan EPR to improve detection sensitivity for spin-trapped radicals. Biophys J 105:338-42|
|Tseitlin, Mark; Eaton, Gareth R; Eaton, Sandra S (2013) Computationally Efficient Steady-State Solution of the Bloch Equations for Rapid Sinusoidal Scans Based on Fourier Expansion in Harmonics of the Scan Frequency. Appl Magn Reson 44:1373-1379|
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