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Signal amplification by reversible exchange

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https://www.readbyqxmd.com/read/29102821/direct-enhancement-of-nitrogen-15-targets-at-high-field-by-fast-adapt-sabre
#1
Soumya S Roy, Gabriele Stevanato, Peter J Rayner, Simon B Duckett
Signal Amplification by Reversible Exchange (SABRE) is an attractive nuclear spin hyperpolarization technique capable of huge sensitivity enhancement in nuclear magnetic resonance (NMR) detection. The resonance condition of SABRE hyperpolarization depends on coherent spin mixing, which can be achieved naturally at a low magnetic field. The optimum transfer field to spin-1/2 heteronuclei is technically demanding, as it requires field strengths weaker than the earth's magnetic field for efficient spin mixing...
October 21, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29044168/squid-based-detection-of-ultra-low-field-multinuclear-nmr-of-substances-hyperpolarized-using-signal-amplification-by-reversible-exchange
#2
K Buckenmaier, M Rudolph, C Back, T Misztal, U Bommerich, P Fehling, D Koelle, R Kleiner, H A Mayer, K Scheffler, J Bernarding, M Plaumann
Ultra-low-field (ULF) nuclear magnetic resonance (NMR) is a promising spectroscopy method allowing for, e.g., the simultaneous detection of multiple nuclei. To overcome the low signal-to-noise ratio that usually hampers a wider application, we present here an alternative approach to ULF NMR, which makes use of the hyperpolarizing technique signal amplification by reversible exchange (SABRE). In contrast to standard parahydrogen hyperpolarization, SABRE can continuously hyperpolarize 1 H as well as other MR-active nuclei...
October 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28644918/heterogeneous-microtesla-sabre-enhancement-of-15-n-nmr-signals
#3
Kirill V Kovtunov, Larisa M Kovtunova, Max E Gemeinhardt, Andrey V Bukhtiyarov, Jonathan Gesiorski, Valerii I Bukhtiyarov, Eduard Y Chekmenev, Igor V Koptyug, Boyd M Goodson
The hyperpolarization of heteronuclei via signal amplification by reversible exchange (SABRE) was investigated under conditions of heterogeneous catalysis and microtesla magnetic fields. Immobilization of [IrCl(COD)(IMes)], [IMes=1,3-bis(2,4,6-trimethylphenyl), imidazole-2-ylidene; COD=cyclooctadiene] catalyst onto silica particles modified with amine linkers engenders an effective heterogeneous SABRE (HET-SABRE) catalyst that was used to demonstrate a circa 100-fold enhancement of (15) N NMR signals in (15) N-pyridine at 9...
August 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28609572/achieving-high-levels-of-nmr-hyperpolarization-in-aqueous-media-with-minimal-catalyst-contamination-using-sabre
#4
Wissam Iali, Alexandra M Olaru, Gary G R Green, Simon B Duckett
Signal amplification by reversible exchange (SABRE) is shown to allow access to strongly enhanced (1) H NMR signals in a range of substrates in aqueous media. To achieve this outcome, phase-transfer catalysis is exploited, which leads to less than 1.5×10(-6)  mol dm(-3) of the iridium catalyst in the aqueous phase. These observations reflect a compelling route to produce a saline-based hyperpolarized bolus in just a few seconds for subsequent in vivo MRI monitoring. The new process has been called catalyst separated hyperpolarization through signal amplification by reversible exchange or CASH-SABRE...
August 4, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28517362/the-absence-of-quadrupolar-nuclei-facilitates-efficient-13-c-hyperpolarization-via-reversible-exchange-with-parahydrogen
#5
Danila A Barskiy, Roman V Shchepin, Christian P N Tanner, Johannes F P Colell, Boyd M Goodson, Thomas Theis, Warren S Warren, Eduard Y Chekmenev
Nuclear spin hyperpolarization techniques are revolutionizing the field of (13) C molecular MRI. While dissolution dynamic nuclear polarization (d-DNP) is currently the leading technique, it is generally slow (requiring ≈1 h) and costly (≈$USD10(6) ). As a consequence of carbon's central place in biochemistry, tremendous progress using (13) C d-DNP bioimaging has been demonstrated to date including a number of clinical trials. Despite numerous attempts to develop alternatives to d-DNP, the competing methods have faced significant translational challenges...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28497481/harnessing-polarisation-transfer-to-indazole-and-imidazole-through-signal-amplification-by-reversible-exchange-to-improve-their-nmr-detectability
#6
Marianna Fekete, Peter J Rayner, Gary G R Green, Simon B Duckett
The signal amplification by reversible exchange (SABRE) approach has been used to hyperpolarise the substrates indazole and imidazole in the presence of the co-ligand acetonitrile through the action of the precataysts [IrCl(COD)(IMes)] and [IrCl(COD)(SIMes)]. (2) H-labelled forms of these catalysts were also examined. Our comparison of the two precatalysts [IrCl(COD)(IMes)] and [IrCl(COD)(SIMes)], coupled with (2) H labelling of the N-heterocyclic carbene and associated relaxation and polarisation field variation studies, demonstrates the critical and collective role these parameters play in controlling the efficiency of signal amplification by reversible exchange...
October 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28443329/direct-hyperpolarization-of-nitrogen-15-in-aqueous-media-with-parahydrogen-in-reversible-exchange
#7
Johannes F P Colell, Meike Emondts, Angus W J Logan, Kun Shen, Junu Bae, Roman V Shchepin, Gerardo X Ortiz, Peter Spannring, Qiu Wang, Steven J Malcolmson, Eduard Y Chekmenev, Martin C Feiters, Floris P J T Rutjes, Bernhard Blümich, Thomas Theis, Warren S Warren
Signal amplification by reversible exchange (SABRE) is an inexpensive, fast, and even continuous hyperpolarization technique that uses para-hydrogen as hyperpolarization source. However, current SABRE faces a number of stumbling blocks for translation to biochemical and clinical settings. Difficulties include inefficient polarization in water, relatively short-lived (1)H-polarization, and relatively limited substrate scope. Here we use a water-soluble polarization transfer catalyst to hyperpolarize nitrogen-15 in a variety of molecules with SABRE-SHEATH (SABRE in shield enables alignment transfer to heteronuclei)...
June 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28392884/generalizing-extending-and-maximizing-nitrogen-15-hyperpolarization-induced-by-parahydrogen-in-reversible-exchange
#8
Johannes F P Colell, Angus W J Logan, Zijian Zhou, Roman V Shchepin, Danila A Barskiy, Gerardo X Ortiz, Qiu Wang, Steven J Malcolmson, Eduard Y Chekmenev, Warren S Warren, Thomas Theis
Signal Amplification by Reversible Exchange (SABRE) is a fast and convenient NMR hyperpolarization method that uses cheap and readily available para-hydrogen as a hyperpolarization source. SABRE can hyperpolarize protons and heteronuclei. Here we focus on the heteronuclear variant introduced as SABRE-SHEATH (SABRE in SHield Enables Alignment Transfer to Heteronuclei) and nitrogen-15 targets in particular. We show that (15)N-SABRE works more efficiently and on a wider range of substrates than (1)H-SABRE, greatly generalizing the SABRE approach...
March 30, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/28377523/delivering-strong-1-h-nuclear-hyperpolarization-levels-and-long-magnetic-lifetimes-through-signal-amplification-by-reversible-exchange
#9
Peter J Rayner, Michael J Burns, Alexandra M Olaru, Philip Norcott, Marianna Fekete, Gary G R Green, Louise A R Highton, Ryan E Mewis, Simon B Duckett
Hyperpolarization turns typically weak NMR and MRI responses into strong signals so that ordinarily impractical measurements become possible. The potential to revolutionize analytical NMR and clinical diagnosis through this approach reflect this area's most compelling outcomes. Methods to optimize the low-cost parahydrogen-based approach signal amplification by reversible exchange with studies on a series of biologically relevant nicotinamides and methyl nicotinates are detailed. These procedures involve specific (2)H labeling in both the agent and catalyst and achieve polarization lifetimes of ca 2 min with 50% polarization in the case of methyl-4,6-d2 -nicotinate...
April 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28183024/high-field-hyperpolarization-exsy-experiment-for-fast-determination-of-dissociation-rates-in-sabre-complexes
#10
Niels K J Hermkens, Martin C Feiters, Floris P J T Rutjes, Sybren S Wijmenga, Marco Tessari
SABRE (Signal Amplification By Reversible Exchange) is a nuclear spin hyperpolarization technique based on the reversible concurrent binding of small molecules and para-hydrogen (p-H2) to an iridium metal complex in solution. At low magnetic field, spontaneous conversion of p-H2 spin order to enhanced longitudinal magnetization of the nuclear spins of the other ligands occurs. Subsequent complex dissociation results in hyperpolarized substrate molecules in solution. The lifetime of this complex plays a crucial role in attained SABRE NMR signal enhancements...
March 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/27934314/iridium-cyclooctene-complex-that-forms-a-hyperpolarization-transfer-catalyst-before-converting-to-a-binuclear-c-h-bond-activation-product-responsible-for-hydrogen-isotope-exchange
#11
Wissam Iali, Gary G R Green, Sam J Hart, Adrian C Whitwood, Simon B Duckett
[IrCl(COE)2]2 (1) reacts with pyridine (py) and H2 to form crystallographically characterized IrCl(H)2(COE)(py)2 (2). 2 undergoes py loss to form 16-electron IrCl(H)2(COE)(py) (3), with equivalent hydride ligands. When this reaction is studied with parahydrogen, 1 efficiently achieves hyperpolarization of free py (and nicotinamide, nicotine, 5-aminopyrimidine, and 3,5-lutudine) via signal amplification by reversible exchange (SABRE) and hence reflects a simple and readily available precatayst for this process...
November 21, 2016: Inorganic Chemistry
https://www.readbyqxmd.com/read/27904890/using-signal-amplification-by-reversible-exchange-sabre-to-hyperpolarise-119-sn-and-29-si-nmr-nuclei
#12
Alexandra M Olaru, Alister Burt, Peter J Rayner, Sam J Hart, Adrian C Whitwood, Gary G R Green, Simon B Duckett
The hyperpolarisation of the (119)Sn and (29)Si nuclei in 5-(tributylstannyl)pyrimidine (ASn) and 5-(trimethylsilyl)pyrimidine (BSi) is achieved through their reaction with [IrCl(COD)(IMes)] (1a) or [IrCl(COD)(SIMes)] (1b) and parahydrogen via the SABRE process. 1a exhibits superior activity in both cases. The two inequivalent pyrimidine proton environments of ASn readily yielded signal enhancements totalling ∼2300-fold in its (1)H NMR spectrum at a field strength of 9.4 T, with the corresponding (119)Sn signal being 700 times stronger than normal...
December 13, 2016: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/27862799/a-hyperpolarizable-1-h-magnetic-resonance-probe-for-signal-detection-15%C3%A2-minutes-after-spin-polarization-storage
#13
Soumya S Roy, Philip Norcott, Peter J Rayner, Gary G R Green, Simon B Duckett
Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are two extremely important techniques with applications ranging from molecular structure determination to human imaging. However, in many cases the applicability of NMR and MRI are limited by inherently poor sensitivity and insufficient nuclear spin lifetime. Here we demonstrate a cost-efficient and fast technique that tackles both issues simultaneously. We use the signal amplification by reversible exchange (SABRE) technique to hyperpolarize the target (1) H nuclei and store this polarization in long-lived singlet (LLS) form after suitable radiofrequency (rf) pulses...
December 12, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27711398/long-lived-states-to-sustain-sabre-hyperpolarised-magnetisation
#14
Soumya S Roy, Peter J Rayner, Philip Norcott, Gary G R Green, Simon B Duckett
The applicability of the magnetic resonance (MR) technique in the liquid phase is limited by poor sensitivity and short nuclear spin coherence times which are insufficient for many potential applications. Here we illustrate how it is possible to address both of these issues simultaneously by harnessing long-lived hyperpolarised spin states that are formed by adapting the Signal Amplification by Reversible Exchange (SABRE) technique. We achieve more than 4% net (1)H-polarisation in a long-lived form that remains detectable for over ninety seconds by reference to proton pairs in the biologically important molecule nicotinamide and a pyrazine derivative whose in vivo imaging will offer a new route to probe disease in the future...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27566396/microparticle-based-rt-qpcr-for-highly-selective-rare-mutation-detection
#15
Eun Hae Oh, Seungwon Jung, Won Jin Kim, Kwang Pyo Kim, Sang Kyung Kim
The quantitative reverse transcription polymerase chain reaction (RT-qPCR) has become one of the most widely used methods in the detection of disease-specific RNAs. The RT-qPCR involves two separate steps, RT and qPCR. In this study, we suggest a new RT-qPCR protocol with the particles of primer-immobilized networks (PINs), performing capture, RT and amplification of a target RNA in one particle. The production of undesired cDNAs was dramatically suppressed by the specific capture of the target RNA within the particle...
January 15, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27500206/nmr-signal-amplification-by-reversible-exchange-of-sulfur-heterocyclic-compounds-found-in-petroleum
#16
Roman V Shchepin, Danila A Barskiy, Aaron M Coffey, Boyd M Goodson, Eduard Y Chekmenev
NMR hyperpolarization via Signal Amplification by Reversible Exchange (SABRE) was employed to investigate the feasibility of enhancing the NMR detection sensitivity of sulfur-heterocycles (specifically 2-methylthiophene and dibenzothiophenes), a family of compounds typically found in petroleum and refined petroleum products. SABRE hyperpolarization of sulfur-heterocycles (conducted in seconds) offers potential advantages of providing structural information about sulfur-containing contaminants in petroleum, thereby informing petroleum purification and refining to minimize sulfur content in refined products such as gasoline...
July 1, 2016: ChemistrySelect
https://www.readbyqxmd.com/read/27495362/perspectives-on-hyperpolarised-solution-state-magnetic-resonance-in-chemistry
#17
Jean-Nicolas Dumez
This perspective article reviews some of the recent developments in the field of hyperpolarisation, with a focus on solution-state NMR spectroscopy of small molecules. Two techniques are considered in more detail, dissolution dynamic nuclear polarisation (D-DNP) and signal amplification by reversible exchange (SABRE). Some of the opportunities and challenges for applications of hyperpolarised solution-state magnetic resonance in chemistry are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
January 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/27379344/-15-n-hyperpolarization-of-imidazole-15-n2-for-magnetic-resonance-ph-sensing-via-sabre-sheath
#18
Roman V Shchepin, Danila A Barskiy, Aaron M Coffey, Thomas Theis, Fan Shi, Warren S Warren, Boyd M Goodson, Eduard Y Chekmenev
(15)N nuclear spins of imidazole-(15)N2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A (15)N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole-(15)N2 in methanol:aqueous buffer (∼1:1). Proton binding to a (15)N site of imidazole occurs at physiological pH (pKa ∼ 7.0), and the binding event changes the (15)N isotropic chemical shift by ∼30 ppm...
June 24, 2016: ACS Sensors
https://www.readbyqxmd.com/read/27350846/aqueous-nmr-signal-enhancement-by-reversible-exchange-in-a-single-step-using-water-soluble-catalysts
#19
Fan Shi, Ping He, Quinn A Best, Kirsten Groome, Milton L Truong, Aaron M Coffey, Greg Zimay, Roman V Shchepin, Kevin W Waddell, Eduard Y Chekmenev, Boyd M Goodson
Two synthetic strategies are investigated for the preparation of water-soluble iridium-based catalysts for NMR signal amplification by reversible exchange (SABRE). In one approach, PEGylation of a variant N-heterocyclic carbene provided a novel catalyst with excellent water solubility. However, while SABRE-active in ethanol solutions, the catalyst lost activity in >50% water. In a second approach, synthesis of a novel di-iridium complex precursor where the cyclooctadiene (COD) rings have been replaced by CODDA (1,2-dihydroxy-3,7-cyclooctadiene) leads to the creation of a catalyst [IrCl(CODDA)IMes] that can be dissolved and activated in water-enabling aqueous SABRE in a single step, without need for either an organic cosolvent or solvent removal followed by aqueous reconstitution...
June 9, 2016: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/27321159/over-20-15-n-hyperpolarization-in-under-one-minute-for-metronidazole-an-antibiotic-and-hypoxia-probe
#20
Danila A Barskiy, Roman V Shchepin, Aaron M Coffey, Thomas Theis, Warren S Warren, Boyd M Goodson, Eduard Y Chekmenev
Direct NMR hyperpolarization of naturally abundant (15)N sites in metronidazole is demonstrated using SABRE-SHEATH (Signal Amplification by Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei). In only a few tens of seconds, nuclear spin polarization P(15)N of up to ∼24% is achieved using parahydrogen with 80% para fraction corresponding to P(15)N ≈ 32% if ∼100% parahydrogen were employed (which would translate to a signal enhancement of ∼0.1-million-fold at 9.4 T). In addition to this demonstration on the directly binding (15)N site (using J(2)H-(15)N), we also hyperpolarized more distant (15)N sites in metronidazole using longer-range spin-spin couplings (J(4)H-(15)N and J(5)H-(15)N)...
July 6, 2016: Journal of the American Chemical Society
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