Article
Biochemistry & Molecular Biology
Kerti Ausmees, Nele Reimets, Indrek Reile
Summary: Parahydrogen hyperpolarization is a promising tool for sensitively enhancing NMR metabolomics, allowing for resolution and quantification of low-abundance metabolites. The reliable identification of analytes producing parahydrogen hyperpolarized NMR signals currently requires the addition of internal standards, which can be laborious. This study demonstrates that generating libraries of hyperpolarized analyte signals, similar to regular NMR metabolomics, can address this limitation.
Article
Chemistry, Multidisciplinary
Victor Ribay, Arnab Dey, Benoit Charrier, Clement Praud, Joris Mandral, Jean-Nicolas Dumez, Marine P. M. Letertre, Patrick Giraudeau
Summary: Hyperpolarized nuclear magnetic resonance (NMR) methods, particularly Dissolution Dynamic Nuclear Polarization (d-DNP), greatly enhance the sensitivity of detecting C-13 NMR signals. This study demonstrates the first application of d-DNP-enhanced C-13 NMR analysis of biofluid (urine) at natural abundance, providing unprecedented resolution and sensitivity. Accurate quantitative information on multiple targeted metabolites can be obtained through a standard addition procedure.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Kai-Oliver Brenske, Meike Emondts, Sven T. Hoernig, Sinan Panitz, Maria I. Pieper, Aron Ligori, Alexander Schacht, Johanna Henkel, Juergen Klankermayer, Andreas Herrmann
Summary: Enhancing the NMR signals of biomacromolecules by hyperpolarization is challenging due to the requirement of specific catalytic interactions and the large size and insolubility of the biomolecules. In this study, we achieved unprecedented hyperpolarization of the cancer-targeting DNA aptamer AS1411 by screening different molecular motifs and adjusting the polarity of AS1411. The results have the potential to advance hyperpolarized molecular imaging technology for disease detection.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
O. Bondar, E. Cavallari, C. Carrera, S. Aime, F. Reineri
Summary: ParaHydrogen Induced Polarization-Side Arm Hydrogenation (PHIP-SAH) is an inexpensive tool for obtaining hyperpolarized pyruvate for in vivo diagnostics. The solvent used in the hydrogenation process can affect efficiency and hyperpolarization level. Coordinating solvents can significantly increase efficiency or hyperpolarization level, but may not be compatible with metabolic applications. The extraction of hyperpolarized product in an aqueous solution can improve biocompatibility by removing traces of organic solvents.
Article
Chemistry, Multidisciplinary
Baptiste Joalland, Thomas Theis, Stephan Appelt, Eduard Y. Chekmenev
Summary: This study demonstrates the utility of Radiofrequency Amplification by Stimulated Emission Radiation (RASER) for background-free proton detection of hyperpolarized biomolecules in a clinically relevant magnetic field. The results show that RASER detection without radio-frequency excitation could pave the way to new applications in high-resolution NMR spectroscopy and in vivo spectroscopy and imaging.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
J. Eills, E. Cavallari, R. Kircher, G. Di Matteo, C. Carrera, L. Dagys, M. H. Levitt, K. L. Ivanov, S. Aime, F. Reineri, K. Muennemann, D. Budker, G. Buntkowsky, S. Knecht
Summary: This study introduces a novel H-1 imaging method in which hyperpolarized spin order is released for imaging through a specific biochemical reaction, while suppressing background signals from water. It allows for hyperpolarized imaging without the need for low-abundance, low-sensitivity heteronuclei.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Christopher Nelson, Andreas B. Schmidt, Isaiah Adelabu, Shiraz Nantogma, Valerij G. Kiselev, Abubakar Abdurraheem, Henri de Maissin, Soeren Lehmkuhl, Stephan Appelt, Thomas Theis, Eduard Y. Chekmenev
Summary: The feasibility of Carbon-13 Radiofrequency (RF) Amplification by Stimulated Emission of Radiation (C-13 RASER) is demonstrated on a bolus of liquid hyperpolarized ethyl [1-C-13]acetate. The study successfully observed C-13 RASER signals and demonstrated its potential application on biomolecular carriers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Patrick M. TomHon, Suyong Han, Soren Lehmkuhl, Stephan Appelt, Eduard Y. Chekmenev, Milad Abolhasani, Thomas Theis
Summary: The Spin Transfer Automated Reactor (STAR) introduced in the study can continuously produce stable parahydrogen induced polarization (PHIP) using the signal amplification by reversible exchange (SABRE) variant. Operated with both benchtop and high field NMR magnets, the STAR efficiently delivers parahydrogen into solutions for hyperpolarization of various substrates. The unique features of the STAR are leveraged for important applications, such as continuous hyperpolarization of metabolites and continuous RASER signals for exploring new physics.
Article
Chemistry, Multidisciplinary
Patrick TomHon, Mustapha Abdulmojeed, Isaiah Adelabu, Shiraz Nantogma, Mohammad Shah Hafez Kabir, Soren Lehmkuhl, Eduard Y. Chekmenev, Thomas Theis
Summary: This study introduces a temperature cycling method for SABRE-SHEATH that enables >10% polarization on [1-C-13]-pyruvate, sufficient for successful in vivo experiments. By using SABRE catalyst-bound pyruvate at lower temperatures, approximately 20% polarization is accumulated and released into free pyruvate at elevated temperatures. A kinetic model of differential equations is developed to explain this effect and characterize critical relaxation and buildup parameters, demonstrating the combination of inexpensive hyperpolarization methods with low-cost MRI systems to achieve a broadly available, yet highly sensitive metabolic imaging platform.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Ewoud Vaneeckhaute, Jean-Max Tyburn, James G. Kempf, Johan A. Martens, Eric Breynaert
Summary: Amino acids and ammonia are essential metabolic markers for nitrogen metabolism and cellular regulation. This study demonstrates a high-field approach using NMR to investigate these metabolic pathways, providing a valuable alternative to existing techniques. By designing a specialized catalyst, spin order can be transferred from p-H-2 to N-15, allowing for reversible hyperpolarization of alanine and ammonia under ambient conditions. The stereochemistry and kinetics of these catalyst complexes are determined using isotopological fingerprinting and 2D-ZQ-NMR.
Article
Chemistry, Multidisciplinary
Nuwandi M. Ariyasingha, Anna Samoilenko, Jonathan R. Birchall, Md Raduanul H. Chowdhury, Oleg G. Salnikov, Larisa M. Kovtunova, Valerii I. Bukhtiyarov, David C. Zhu, Chunqi Qian, Michael Bradley, Juri G. Gelovani, Igor V. Koptyug, Boyd M. Goodson, Eduard Y. Chekmenev
Summary: Hyperpolarized MRI contrast agents are revolutionizing biomedical imaging. Researchers have demonstrated a low-cost, handheld device for producing hyperpolarized protonated propane gas, which has potential applications in clinical settings.
Article
Chemistry, Physical
Jing Yang, Peng Wang, Jan G. Korvink, Juergen J. Brandner, Soeren Lehmkuhl
Summary: A method to control the operation of a RASER at a magnetic field of 1.45 T is introduced, using a continuous-flow RASER pumped by PHIP. The system demonstrates five RASER phenomena and matches with simulations based on a theoretical model of two nonlinear-coupled RASER modes.
Article
Chemistry, Physical
Oleg G. Salnikov, Nikita Chukanov, Larisa M. Kovtunova, Valerii Bukhtiyarov, Kirill Kovtunov, Roman Shchepin, Igor Koptyug, Eduard Y. Chekmenev
Summary: The efficiency of H-1 and C-13 hyperpolarization of acetate and pyruvate esters using heterogeneous hydrogenation and parahydrogen over Rh/TiO2 catalysts was investigated. Acetate esters surpassed pyruvates in hyperpolarization, and esters with a double bond in unsaturated alcoholic moieties were more efficient than those with a triple carbon-carbon bond. Among the compounds studied, propyl acetate yielded the maximum H-1 and C-13 NMR signal intensities.
Article
Chemistry, Physical
Isaiah Adelabu, Patrick TomHon, Mohammad S. H. Kabir, Shiraz Nantogma, Mustapha Abdulmojeed, Iuliia Mandzhieva, Jessica Ettedgui, Rolf E. Swenson, Murali C. Krishna, Thomas Theis, Boyd M. Goodson, Eduard Y. Chekmenev
Summary: Signal Amplification By Reversible Exchange in SHield Enabled Alignment Transfer (SABRE-SHEATH) was investigated for rapid hyperpolarization of C-13(1) spins of [1-C-13]pyruvate using parahydrogen. The exchange of pyruvate with an iridium polarization transfer complex can be modulated by temperature and co-ligation conditions. Efficient C-13 polarization was achieved in less than 30 seconds by restricting the chemical exchange of [1-C-13]pyruvate at lower temperatures, with the possibility of fast release for future biomedical applications.
Article
Chemistry, Physical
Vladimir V. Zhivonitko, Henrik Beer, Danila O. Zakharov, Jonas Bresien, Axel Schulz
Summary: The activation of parahydrogen by 4- and 5-membered pnictogen biradicaloids has been studied, allowing for observation of strong nuclear spin hyperpolarization effects in H-1 and P-31 NMR experiments. Reversible activation of H-2 was demonstrated by 4-membered biradicaloids, leading to SABRE hyperpolarization, while 5-membered biradicaloids showed irreversible parahydrogen activation.
Article
Chemistry, Applied
Mihkel Saluri, Kadri-Liis Kaljuvee, Tiina Paalme, Indrek Reile, Rando Tuvikene
Summary: Furcellaran samples extracted from both drifting and attached forms of red algae Furcellaria lumbricalis collected from the Estonian waters were characterised and their properties were examined. Results showed the presence of sulphate ester groups, nearly equimolar amounts of beta- and kappa-carrageenans, and higher molecular weights for samples extracted from attached specimens. The gels formed by furcellaran samples exhibited decreased storage moduli with reduced KCl concentrations, and had a significant degree hysteresis in certain conditions.
FOOD HYDROCOLLOIDS
(2021)
Article
Biochemistry & Molecular Biology
Kerti Ausmees, Nele Reimets, Indrek Reile
Summary: Parahydrogen hyperpolarization is a promising tool for sensitively enhancing NMR metabolomics, allowing for resolution and quantification of low-abundance metabolites. The reliable identification of analytes producing parahydrogen hyperpolarized NMR signals currently requires the addition of internal standards, which can be laborious. This study demonstrates that generating libraries of hyperpolarized analyte signals, similar to regular NMR metabolomics, can address this limitation.
Article
Chemistry, Medicinal
Piret Saar-Reismaa, Olga Bragina, Maria Kuhtinskaja, Indrek Reile, Pille-Riin Laanet, Maria Kulp, Merike Vaher
Summary: This study evaluated the activity of Dipsacus fullonum L. leaves extract (DE) and its fractions against stationary phase B. burgdorferi in vitro. DE showed high activity against the bacteria, while also exhibiting cytotoxicity. Further purification of the iridoid-glycoside fraction revealed two main bioactives that had considerable anti-Borrelia activity with minimal toxicity to cells.
Article
Oncology
Aleksandr Klepinin, Sten Miller, Indrek Reile, Marju Puurand, Egle Rebane-Klemm, Ljudmila Klepinina, Heiki Vija, Song Zhang, Andre Terzic, Petras Dzeja, Tuuli Kaambre
Summary: The dynamics of ATP phosphoryl turnover and metabolic flux through phosphotransfer pathways in cancer cells are not well understood. In this study, using O-18 phosphometabolite tagging technology, the authors investigated the phosphotransfer dynamics in three breast cancer cell lines and found a decreased turnover of γ- and β-ATP in cancer cells compared to control. They also observed reduced fluxes through HK, CK, and mitochondrial substrate shuttle in aggressive cancer cells. The downregulation of MTCK1A was linked to the decreased CK metabolic flux. However, overexpression of HK2, AK2, and AK6 isoforms in cell compartments could promote aggressive breast cancer growth.
FRONTIERS IN ONCOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Bijan Barghi, Martin Jurisoo, Maria Volokhova, Liis Seinberg, Indrek Reile, Valdek Mikli, Allan Niidu
Summary: This research investigates the catalytic performance of a metal-organic framework (MOF) with a functionalized ligand, UiO-66-NH2, in the oxidative desulfurization of dibenzothiophene (DBT) in a model fuel mixture (MFM). The optimal reaction conditions were determined, and the reusability of the MOF catalyst was tested.
Article
Chemistry, Organic
Jaan Parve, Marina Kudryashova, Tatsiana Shalima, Ly Villo, Moonika Ferschel, Allan Niidu, Ilme Liblikas, Indrek Reile, Riina Aav, Nicholas Gathergood, Lauri Vares, Tonis Pehk, Omar Parve
Summary: Scalable protocols for the synthesis of enantiomeric gamma-(acyloxy)carboxylic acids and gamma-lactones are presented. The key step involves lipase-catalyzed acylation of gamma-hydroxycarboxylic acid sodium salt, followed by acidification, extraction, and relactonization. The enantioinduction of Candida antarctica lipase B switches from R to S configuration for longer-chain homologues. Both enantiomers of gamma-(acyloxy)pentanoic acids and S-configured gamma-lactones were prepared with high selectivity. The rates of acylation differ for different chain lengths but can be controlled by adjusting the enzyme loading and reaction time.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jasper Adamson, Helena Roithmeyer, Merle Uudsemaa, Aleksander Trummal, Mari-Liis Bruk, Sebastian Kramer, Indrek Reile, Vitalijs Rjabovs, Kirsti Palmi, Matt Rammo, Riina Aav, Elina Kalenius
Summary: In this study, a series of new switchable azobenzene macrocycles with 10 to 40 aromatic rings were detected using mass spectrometry, ion mobility (IM) mass spectrometry, and NMR experiments. The photo-switching responsiveness of the smallest macrocycle with 2 azobenzene units and 10 aromatic rings was studied through irradiation experiments and UV-Vis absorption and NMR spectroscopy. DFT calculations were used to understand the conformation of this isolated species in solution.
SUPRAMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Analytical
Nele Reimets, Kerti Ausmees, Sirje Vija, Aleksander Trummal, Merle Uudsemaa, Indrek Reile
Summary: This study demonstrates the application of parahydrogen hyperpolarization in NMR analysis of underivatized oligopeptides in solution. The authors investigate the structure of the oligopeptide and hyperpolarization catalyst complexes formed and show that different coordination modes of alanine oligomers with the iridium carbene-based catalyst result in distinctive hydride signals. The study provides insights into the interaction between the organometallic iridium-N-heterocyclic carbene-based catalyst and biopolymers, and demonstrates the detection of underivatized oligopeptides in urine using parahydrogen hyperpolarized NMR.
Article
Polymer Science
Elvira Tarasova, Nutan Savale, Illia Krasnou, Marina Kudrjasova, Vitalijs Rjabovs, Indrek Reile, Lauri Vares, Heikko Kallakas, Jaan Kers, Andres Krumme
Summary: This study synthesized various cellulose esters in an ionic liquid medium, which is an environmentally friendly alternative to conventional esterification. The results showed that the degree of substitution of cellulose esters increased with reaction time, temperature, and added vinyl esters. Structure analysis and thermal-rheological investigation revealed that the substitution of cellulose with acyl chains increased the melt viscosity of the material.
Review
Chemistry, Multidisciplinary
Dan He, Yawen Li, Fuwen Zhao, Yuze Lin
Summary: High trap density in organic solar cells leads to localized charge carriers and reduced carrier lifetime, limiting device efficiency. This feature article summarizes the recent advances of trap suppression by material design and device engineering.
CHEMICAL COMMUNICATIONS
(2024)
Review
Chemistry, Multidisciplinary
Olivier Monfort, Arshitha Madhusudhan, Martin Motola
Summary: This article presents the advantages of coupling photocatalysis and Fenton-based processes for environmental remediation and discusses their synergy. It critically examines the simultaneous triggering of these two processes and provides insights into research approaches. The study aims to enhance understanding of this complex process and highlight the potential integration of new catalysts in current wastewater treatment technology.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Manideepa Dhar, Chittaranjan Mishra, Avijit Das, Uttam Manna
Summary: An approach of 'polymerization of monomers in its aggregated form' has been introduced to tailor the water wettability of fibrous and porous substrates, achieving hydrophobicity to superhydrophobicity transition, as well as patterned wettability. This facile chemical method provides a durable coating with adjustable and patterned wettability for various potential applications.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Saswat Ranjan Bhoi, Chhanda Debnath, Shikha Gandhi
Summary: In this article, a novel catalytic reaction using Pd(0) and Bronsted acid is reported for the synthesis of biologically important imidazolidinone-fused N-heterocycles through redox-neutral intramolecular N-allylation of indoles and pyrroles with alkynes. This atom-economical method is applicable to a wide range of substrates and eliminates the need for leaving groups or oxidizing agents commonly used in traditional allylation reactions.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Longkun Chen, Mingshuai Zhang, Meichen Liu, Zhuoyuan Liu, Yuetong Qiu, Zhilai Zhang, Fuchao Yu, Jiuzhong Huang
Summary: In this study, an efficient Rh(III)-catalyzed selective mono- and dual-C-H bond functionalization/cyclization with iodonium ylide as the sole coupling partner was demonstrated. Fused benzodiazepine skeletons were obtained in excellent yields, providing an improved approach to dual C-H unsymmetrical functionalization.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Alice Kennett, Sven Epple, Gabriella van der Valk, Irene Georgiou, Evelyne Gout, Romain R. Vives, Angela J. Russell
Summary: This study presents the design and synthesis of sulfated disaccharide inhibitors based on IdoA(2S)-GlcNS(6S), which showed potent inhibition of Sulf-2. The results suggest that IdoA(2S)-GlcNS(6S) is the shortest fragment size required for effective inhibition of Sulfs, and a trisulfated disaccharide is identified as the minimal fragment size of heparan sulfate for effective endosulfatase inhibition.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Mauro Garbini, Andrea Brunetti, Riccardo Pedrazzani, Magda Monari, Massimo Marcaccio, Giulio Bertuzzi, Marco Bandini
Summary: The self-adaptability of galvanostatic electrolysis was found to be helpful in a multistage chemo- and diastereoselective electrochemically promoted cyclodimerization of chalcones. Through a series of reductive events, densely functionalized cyclopentanes with five contiguous stereocenters were obtained (25 examples, yields up to 95%, dr values up to >20:1). Further experimental and electrochemical investigations indicated the crucial role of dynamic kinetic resolution of the aldol intermediate in the reaction mechanism.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Dhananjay S. Nipate, Neha Meena, Prakash N. Swami, Krishnan Rangan, Anil Kumar
Summary: In this study, the synthesis of functionalized benzo[a]phenazines and indazolo[2,3-a]quinolines was achieved through Rh(III)-catalyzed oxidative annulation of 2-arylquinoxalines and 2-aryl-2H-indazoles with allyl alcohols. The method showed a wide substrate scope, excellent functional group tolerance, good to high yields of annulated products, and the capability for scaled-up synthesis. A tentative mechanism of the annulation reaction was proposed based on a preliminary mechanistic investigation.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Ruonan Zhang, Abudukadi Tudi, Xia Yang, Xuping Wang, Zhihua Yang, Shujuan Han, Shilie Pan
Summary: A new lead tellurium borate material with a unique fundamental building block [B4O10] was synthesized and found to exhibit high birefringence. The structure-property relationship was discussed using first-principles calculations.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Amresh Kumar Singh, Baishali Thakurta, Anupam Giri, Monalisa Pal
Summary: This study introduces three key concepts for the quick synthesis of large-scale high-quality 2D materials films and their utilization in device fabrication.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Reina Hagiwara, Shun Nishimura, Kosuke Okeyoshi
Summary: A copolymer-conjugated nanocatalytic system has been developed to improve electron transfer and enhance photoinduced H2 generation.
CHEMICAL COMMUNICATIONS
(2024)
