Publications de David Benjamin Roger Antoine Gajan

Multiple Surface Site Three-Dimensional Structure Determination of a Supported Molecular Catalyst

David Benjamin Roger Antoine Gajan, Pierrick Berruyer, Moreno Lelli, Zhuoran Wang

The structural characterization of supported molecular catalysts is challenging due to the low density of active sites and the presence of several organic/organometallic surface groups resulting from the often complex surface chemistry associated with supp ...

AMER CHEMICAL SOC2022

Atomic-Scale Description of Interfaces between Antigen and Aluminum-Based Adjuvants Used in Vaccines by Dynamic Nuclear Polarization (DNP) Enhanced NMR Spectroscopy

David Benjamin Roger Antoine Gajan, Federico Maria Paruzzo, Jasmine Viger-Gravel

The addition of aluminum-based adjuvants in vaccines enhances the immune response to antigens. The strength of antigen adsorption on adjuvant gels is known to modulate vaccine efficacy. However, a detailed understanding of the mechanisms of interaction bet ...

WILEY-V C H VERLAG GMBH2020

TinyPols: a family of water-soluble binitroxides tailored for dynamic nuclear polarization enhanced NMR spectroscopy at 18.8 and 21.1 T

David Benjamin Roger Antoine Gajan, David Lyndon Emsley, Gabriele Stevanato, Georges Guévork Jean-Jacques Menzildjian, Moreno Lelli

Dynamic Nuclear Polarization (DNP) has recently emerged as a key method to increase the sensitivity of solid-state NMR spectroscopy under Magic Angle Spinning (MAS). While efficient binitroxide polarizing agents such as AMUPol have been developed for MAS D ...

2020

Structural description of surfaces and interfaces in biominerals by DNP SENS

David Benjamin Roger Antoine Gajan, David Lyndon Emsley

Biological mineralized tissues are hybrid materials with complex hierarchical architecture composed of biominerals often embedded in an organic matrix. The atomic-scale comprehension of surfaces and organo-mineral interfaces of these biominerals is of para ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2019

F-19 Magic Angle Spinning Dynamic Nuclear Polarization Enhanced NMR Spectroscopy

David Benjamin Roger Antoine Gajan, Dominik Józef Kubicki, David Lyndon Emsley, Jasmine Viger-Gravel, Claudia Esther Avalos, Moreno Lelli

The introduction of high-frequency, high-power microwave sources, tailored biradicals, and low-temperature magic angle spinning (MAS) probes has led to a rapid development of hyperpolarization strategies for solids and frozen solutions, leading to large ga ...

Wiley-VCH Verlag GmbH2019

BDPA-Nitroxide Biradicals Tailored for Efficient Dynamic Nuclear Polarization Enhanced Solid-State NMR at Magnetic Fields up to 21.1 T

David Benjamin Roger Antoine Gajan, Dominik Józef Kubicki, Arthur César Pinon, David Lyndon Emsley, Aaron James Rossini, Georges Guévork Jean-Jacques Menzildjian, Moreno Lelli

Dynamic nuclear polarization (DNP) solid-state nuclear magnetic resonance (NMR) has developed into an invaluable tool for the investigation of a wide range of materials. However, the sensitivity gain achieved with many polarizing agents suffers from an unf ...

AMER CHEMICAL SOC2018

Predicting the DNP-SENS efficiency in reactive heterogeneous catalysts from hydrophilicity

David Benjamin Roger Antoine Gajan, David Lyndon Emsley, Jasmine Viger-Gravel

2018

The structure and binding mode of citrate in the stabilization of gold nanoparticles

David Benjamin Roger Antoine Gajan, David Lyndon Emsley, Jasmine Viger-Gravel

Elucidating the binding mode of carboxylate-containing ligands to gold nanoparticles (AuNPs) is crucial to understand their stabilizing role. A detailed picture of the three-dimensional structure and coordination modes of citrate, acetate, succinate and gl ...

Nature Publishing Group2017

Phenylazide Hybrid-Silica - Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures

Geoffrey Bodenhausen, Sami Jannin, Aurélien Bornet, Jonas Milani, Basile Vuichoud, David Benjamin Roger Antoine Gajan, David Baudouin

Hyperpolarization of NMR-active nuclei is key to gather high quality spectra of rare species and insensitive isotopes. We have recently established that silica-based materials containing regularly distributed nitroxyl radicals connected to the silica matri ...

Wiley-V C H Verlag Gmbh2017

Transportable hyperpolarized metabolites

Geoffrey Bodenhausen, Sami Jannin, Aurélien Bornet, Jonas Milani, Basile Vuichoud, David Benjamin Roger Antoine Gajan, Xiao Ji, David Lyndon Emsley, Aaron James Rossini

Nuclear spin hyperpolarization of C-13-labelled metabolites by dissolution dynamic nuclear polarization can enhance the NMR signals of metabolites by several orders of magnitude, which has enabled in vivo metabolic imaging by MRI. However, because of the s ...

Nature Publishing Group2017

Frozen Acrylamide Gels as Dynamic Nuclear Polarization Matrices

David Benjamin Roger Antoine Gajan, David Lyndon Emsley, Jasmine Viger-Gravel, Pierrick Berruyer

Aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with crosslinker concentration and low concentrations of the AMUPol biradical ...

Wiley-VCH Verlag GmbH2017

Structured and porous materials particularly suitable as polarizing agents in dissolution dynamic nuclear polarization

Geoffrey Bodenhausen, Sami Jannin, Aurélien Bornet, David Benjamin Roger Antoine Gajan, David Lyndon Emsley, David Baudouin

The present invention concerns materials consisting in a porous and structured network, this network being at least in part formed by Si atoms, or Si atoms and metal atoms, linked to each other by oxy bridges, comprising organic molecules which include at ...

2016

Polymorphs of Theophylline Characterized by DNP Enhanced Solid-State NMR

David Benjamin Roger Antoine Gajan, Arthur César Pinon, David Lyndon Emsley, Aaron James Rossini

We show how dynamic nuclear polarization (DNP) enhanced solid-state NMR spectroscopy can be used to characterize polymorphs and solvates of organic solids. We applied DNP to three polymorphs and one hydrated form of the asthma drug molecule theophylline. F ...

American Chemical Society2015

Hybrid polarizing solids for pure hyperpolarized liquids through dissolution dynamic nuclear polarization

Geoffrey Bodenhausen, Sami Jannin, Aurélien Bornet, Jonas Milani, Basile Vuichoud, David Benjamin Roger Antoine Gajan, David Lyndon Emsley

Hyperpolarization of substrates for magnetic resonance spectroscopy (MRS) and imaging (MRI) by dissolution dynamic nuclear polarization (D-DNP) usually involves saturating the ESR transitions of polarizing agents (PAs; e.g., persistent radicals embedded in ...

National Academy of Sciences2014

Dynamic nuclear polarization of quadrupolar nuclei using cross polarization from protons: surface-enhanced aluminium-27 NMR

Geoffrey Bodenhausen, Pascal Miéville, Marc Anthony Caporini, Diego Carnevale, David Benjamin Roger Antoine Gajan, David Lyndon Emsley, Aaron James Rossini, Moreno Lelli

The surface of gamma-alumina nanoparticles can be characterized by dynamic nuclear polarization (DNP) surface-enhanced NMR of Al-27. DNP is combined with cross-polarization and MQ-MAS to determine local symmetries of Al-27 sites at the surface. ...

Royal Society of Chemistry2012