%0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America %D 2009 %T Picomolar sensitivity MRI and photoacoustic imaging of cobalt nanoparticles %A Bouchard, L. S. %A Anwar, M. S. %A Liu, G. L. %A Hann, B. %A Xie, Z. H. %A Gray, J. W. %A Wang, X. D. %A Pines, A. %A Chen, F. F. %K cancer %X

Multimodality imaging based on complementary detection principles has broad clinical applications and promises to improve the accuracy of medical diagnosis. This means that a tracer particle advantageously incorporates multiple functionalities into a single delivery vehicle. In the present work, we explore a unique combination of MRI and photoacoustic tomography (PAT) to detect picomolar concentrations of nanoparticles. The nanoconstruct consists of ferromagnetic (Co) particles coated with gold (Au) for biocompatibility and a unique shape that enables optical absorption over a broad range of frequencies. The end result is a dual-modality probe useful for the detection of trace amounts of nanoparticles in biological tissues, in which MRI provides volume detection, whereas PAT performs edge detection.

%B Proceedings of the National Academy of Sciences of the United States of America %V 106 %P 4085-4089 %8 Mar 17 %@ 0027-8424 %G English %U ://WOS:000264278800008 %N 11 %M WOS:000264278800008 %! Picomolar sensitivity MRI and photoacoustic imaging of cobalt nanoparticles %R Doi 10.1073/Pnas.0813019106 %0 Journal Article %J Science %D 2008 %T NMR imaging of catalytic hydrogenation in microreactors with the use of para-hydrogen %A Bouchard, L. S. %A Burt, S. R. %A Anwar, M. S. %A Kovtunov, K. V. %A Koptyug, I. V. %A Pines, A. %K chip %X

Catalysis is vital to industrial chemistry, and the optimization of catalytic reactors attracts considerable resources. It has proven challenging to correlate the active regions in heterogeneous catalyst beds with morphology and to monitor multistep reactions within the bed. We demonstrate techniques, using magnetic resonance imaging and para- hydrogen ( p-H(2)) polarization, that allow direct visualization of gas- phase flow and the density of active catalyst in a packed- bed microreactor, as well as control over the dynamics of the polarized state in space and time to facilitate the study of subsequent reactions. These procedures are suitable for characterizing reactors and reactions in microfluidic devices where low sensitivity of conventional magnetic resonance would otherwise be the limiting factor.

%B Science %V 319 %P 442-445 %8 Jan 25 %@ 0036-8075 %G English %U ://WOS:000252576600031 %N 5862 %M WOS:000252576600031 %! NMR imaging of catalytic hydrogenation in microreactors with the use of para-hydrogen %R Doi 10.1126/Science.1151787 %0 Journal Article %J Angewandte Chemie-International Edition %D 2007 %T Para-hydrogen-enhanced hyperpolarized gas-phase magnetic resonance imaging %A Bouchard, L. S. %A Kovtunov, K. V. %A Burt, S. R. %A Anwar, M. S. %A Koptyug, I. V. %A Sagdeev, R. Z. %A Pines, A. %K he-3 %B Angewandte Chemie-International Edition %V 46 %P 4064-4068 %@ 1433-7851 %G English %U ://WOS:000246981900008 %N 22 %M WOS:000246981900008 %! Para-hydrogen-enhanced hyperpolarized gas-phase magnetic resonance imaging %R Doi 10.1002/Anie.200700830 %0 Journal Article %J Journal of the American Chemical Society %D 2007 %T Para-hydrogen-induced polarization in heterogeneous hydrogenation reactions %A Koptyug, I. V. %A Kovtunov, K. V. %A Burt, S. R. %A Anwar, M. S. %A Hilty, C. %A Han, S. I. %A Pines, A. %A Sagdeev, R. Z. %K alignment %X

We demonstrate the creation and observation of para-hydrogen-induced polarization in heterogeneous hydrogenation reactions. Wilkinson's catalyst, RhCl(PPh3)(3), supported on either modified silica gel or a polymer, is shown to hydrogenate styrene into ethylbenzene and to produce enhanced spin polarizations, observed through NMR, when the reaction was performed with H-2 gas enriched in the para spin isomer. Furthermore, gaseous phase para-hydrogenation of propylene to propane with two catalysts, the Wilkinson's catalyst supported on modified silica gel and Rh(cod)(sulfos) (cod = cycloocta-1,5-diene; sulfos = -O3S(C6H4)CH2C(CH2PPh2)(3)) supported on silica gel, demonstrates heterogeneous catalytic conversion resulting in large spin polarizations. These experiments serve as a direct verification of the mechanism of heterogeneous hydrogenation reactions involving immobilized metal complexes and can be potentially developed into a practical tool for producing catalyst-free fluids with highly polarized nuclear spins for a broad range of hyperpolarized NMR and MRI applications.

%B Journal of the American Chemical Society %V 129 %P 5580-5586 %8 May 2 %@ 0002-7863 %G English %U ://WOS:000245946400064 %N 17 %M WOS:000245946400064 %! para-hydrogen-induced polarization in heterogeneous hydrogenation reactions %R Doi 10.1021/Ja068653o %0 Journal Article %J Analytical Chemistry %D 2007 %T Spin coherence transfer in chemical transformations monitored by remote detection NMR %A Anwar, M. S. %A Hilty, C. %A Chu, C. %A Bouchard, L. S. %A Pierce, K. L. %A Pines, A. %K lab %X

We demonstrate a nuclear magnetic resonance (NMR) experiment using continuous flow in a microfluidic channel for studying the transfer of spin coherence in nonequilibrium chemical processes. We use the principle of remote detection, which involves spatially separated NMR encoding and detection coils. As an example, we provide the map of chemical shift correlations for the amino acid alanine as it transitions from the zwitterionic to the anionic form. The presented method uniquely allows for tracking the migration of encoded spins during the course of any chemical transformation and can provide useful information about reaction mechanisms.

%B Analytical Chemistry %V 79 %P 2806-2811 %8 Apr 1 %@ 0003-2700 %G English %U ://WOS:000245304300022 %N 7 %M WOS:000245304300022 %! Spin coherence transfer in chemical transformations monitored by remote detection NMR %R Doi 10.1021/Ac062327+