Exposition la Science Taille XXElles

March 2024

After almost two years of preparation by the CNRS and the association Femmes et Sciences, the photographic exhibition of "la Science Taille XXElles" finally opened to the public. The fantastic pictures taken by Vincent Moncorgé for this beautiful project are exposed in Marseille city center for a month. A beautiful and funny way to celebrate and promote the role of women in science, hoping this will be of inspiration to the young generation.

15/02/2024Visit to University of Abu Dhabi

February 2024

Giulia was invited by Prof. Brijith Thomas to give a seminar to the Chemistry department of the New York University in Adu Dhabi. A day full of discussion, but we managed to find a little time to visit a little bit. Thank you Brijith for this fantastic hospitality!

New paper from the group

January 2024

New paper out! Nice example of how DNP can help investigating frozen solution of Ca ions. Nice collaboration with the group of T. Azais at Sorbonne University.

43Ca MAS-DNP NMR of Frozen Solutions for the Investigation of Calcium Ion Complexation
Tristan Georges, Romain Chèvre, Samuel F. Cousin, Christel Gervais, Pierre Thureau, Giulia Mollica*, and Thierry Azaïs*
ACS Omega, 9 4881-4891 (2024) 

43Ca MAS-DNP NMR of Frozen Solutions for the Investigation of Calcium Ion Complexation

Calcium ion complexation in aqueous solutions is of paramount importance in biology as it is related to cell signaling, muscle contraction, or biomineralization. However, Ca2+-complexes are dynamic soluble entities challenging to describe at the molecular level. Nuclear magnetic resonance appears as a method of choice to probe Ca2+-complexes. However, 43Ca NMR exhibits severe limitations arising from the low natural abundance coupled to the low gyromagnetic ratio and the quadrupolar nature of 43Ca, which overall make it a very unreceptive nucleus. Here, we show that 43Ca dynamic nuclear polarization (DNP) NMR of 43Ca-labeled frozen solutions is an efficient approach to enhance the NMR receptivity of 43Ca and to obtain structural insights about calcium ions complexed with representative ligands including water molecules, ethylenediaminetetraacetic acid (EDTA), and l-aspartic acid (l-Asp). In these conditions and in combination with numerical simulations and calculations, we show that 43Ca nuclei belonging to Ca2+ complexed to the investigated ligands exhibit rather low quadrupolar couplings (with CQ typically ranging from 0.6 to 1 MHz) due to high symmetrical environments and potential residual dynamics in vitrified solutions at a temperature of 100 K. As a consequence, when 1H→43Ca cross-polarization (CP) is used to observe 43Ca central transition, “high-power” νRF(43Ca) conditions, typically used to detect spin 1/2 nuclei, provide ∼120 times larger sensitivity than “low-power” conditions usually employed for detection of quadrupolar nuclei. These “high-power” CPMAS conditions allow two-dimensional (2D) 1H–43Ca HetCor spectra to be readily recorded, highlighting various Ca2+–ligand interactions in solution. This significant increase in 43Ca NMR sensitivity results from the combination of distinct advantages: (i) an efficient 1H-mediated polarization transfer from DNP, resembling the case of low-natural-abundance spin 1/2 nuclei, (ii) a reduced dynamics, allowing the use of CP as a sensitivity enhancement technique, and (iii) the presence of a relatively highly symmetrical Ca environment, which, combined to residual dynamics, leads to the averaging of the quadrupolar interaction and hence to efficient high-power CP conditions. Interestingly, these results indicate that the use of high-power CP conditions is an effective way of selecting symmetrical and/or dynamic 43Ca environments of calcium-containing frozen solution, capable of filtering out more rigid and/or anisotropic 43Ca sites characterized by larger quadrupolar constants. This approach could open the way to the atomic-level investigation of calcium environments in more complex, heterogeneous frozen solutions, such as those encountered at the early stages of calcium phosphate or calcium carbonate biomineralization events.

New paper from the group

December 2023

Congratulations to Nghia for his new paper!

A facile approach for estimating radio-frequency field strength of low-receptivity nuclei
Nghia Tuan Duong, Stéphane Viel, Fabio Ziarelli, Pierre Thureau, Giulia Mollica
J. Magn. Reson., 358 107614 (2024) 

A facile approach for estimating radio-frequency field strength of low-receptivity nuclei

nutation curve by varying the pulse length in a direct single-pulse excitation experiment or in a cross-polarization
magic-angle spinning with a flip-back pulse experiment. From the null points on this curve, one can calculate the
RF field strength. Nevertheless, the practical implementation is not always straightforward or can even be unrealizable,
especially for low-receptivity nuclei owing to their associated low sensitivity. Several researchers used
an approach that involves utilizing other nuclei with more sensitivity but nearly identical Larmor frequencies to
that of the nucleus of interest. However, such an approach has not been a common practice so far. In this work,
we have systematically revisited this approach using 3.2 mm rotors on different sets of nuclei covering a Larmor
frequency range up to 80 MHz. The effect of solid- and solution-states on RF field strength measurements has
been investigated. The detection of each set of nuclei is then carried out with a resonant circuit in the NMR probe
consisting of identical coils and capacitors. Our methodology is illustrated by recording 135/137Ba NMR spectra of
BaTiO3 without prior 135/137Ba RF field calibration.

15/12/2023: Visit to the University of Vienna

December 2023

Giulia was invited by Prof. Dennis Kurzbach to give a seminar at the University of Vienna's Chemistry department. A day full of science in the magnificent Vienna. Thank you Dennis for your hospitality!

Céline and Minh Tu joined the group!

November 2023

Welcome to the group to our PhD students Céline and Minh Tu!

New paper from the group

October 2023

We describe a new sample formulation for MAS DNP, showing that good sensitivity enhancements be obtained in water without glycerol (or other glass forming agents) simply by dissolving
high concentrations of electrolytes (such as NaCl or LiCl), which perturb the otherwise
unavoidable ice crystallization observed upon cooling, thereby reducing PA phase separation
and restoring DNP efficiency.

Polarization Amplification in Dynamic Nuclear Polarization Magic- Angle Spinning Solid-State Nuclear Magnetic Resonance by Solubilizing Traditional Ionic Salts
F. Ferrer, M. Juramy, R. Jabbour, S. Cousin, F. Ziarelli, G. Mollica, P. Thureau, S. Viel.
J. Phys. Chem. Lett., 14 9619 - 9623 (2023) 

Sam and Giulia attended the European Researcher's Night in Marseille

September 2023

Giulia and Sam contributed to the European Researcher's Night in Marseille for the ICR through Speed Searching and Tabou de la Recherche...and met lots of young and old people interested in science.

09/2023 Giulia attended the Alpine Conference in Chamonix

September 2023

Giulia was in Chamonix attending the Alpine Conference in solids where she gave tutorial on Sunday morning on solid state NMR of small molecules, and later during the week a round table presentation of polymorphic transformation in solids detected by MAS DNP. She also officially joined the organizing committee of the Alpine Conference!

08/2023: Giulia attended ISMAR in Brisbane

August 2023

Giulia attended the ISMAR conference in Brisbane (AUS) where she gave an invited lecture on the study of polymorphic phase formation and transformation using hyperpolarized NMR. Stunning city and location, and excellent conference!

Giulia attended IUCr Conference in Melbourne

August 2023

Giulia gave an invited talk to the IUCr conference in Melbourne. Fantastic meeting and location.

07/2023: Pierre gave a talk at Euromar

July 2023

Pierre was at the Euromar 2023 in Glasgow where he gave a presentation on the use of MAS DNP for the early detection of polymorphic transformations in organic solids.

07/2023: Raffaella Demichelis visiting the lab

July 2023

Prof Raffaella Demichelis from Curtin University in Australia visited the lab. She gave a beautiful talk on "Chemistry at the mineral-fluid interface: an atomic-scale perspective", very interesting topic and results. Thanks Raffaella!

07/2023: Romain's PhD defense

July 2023

Romain successfully defended his PhD! Congratulations to him and many thanks to the committee members Marco Geppi, Loriane Lecoq (rapporteurs), Christian Bonhomme and Danielle Laurencin for the nice discussion.

06/2023: Céline will join the group as a PhD candidate in September!

June 2023

Céline Huart is the recipient of a PhD fellowship funded by the University of Aix-Marseille. Her interdisciplinary project will be carried out between the ICR and the CINaM laboratories in Marseille. She will combine hyperpolarized NMR and microfluidics for studying crystallization in confined environements. Stay tuned for exciting discoveries!

New publication from the group!

June 2023

Congratulations to Samuel for his first publication with us! Great collaboration with Arthur Pinon (Gothenburg), Kenneth D.M. Harris and Colan E. Hughes (Cardiff) to show how far DNP can go to reveal the nanoscale morphology of mixtures of organic polymorphs.

Exploiting solid-state dynamic nuclear polarization NMR spectroscopy to establish the spatial distribution of polymorphic phases in a solid material
S.F. Cousin, C.E. Hughes, F. Ziarelli, S. Viel, G. Mollica*, K.D.M. Harris, A.C. Pinon, P. Thureau
Chemical Science, 14 10121 - 10128 (2023) 

06/2023: Giulia and Samuel attended the GERM conference

June 2023

Giulia and Sam attended the GERM conference on NMR in extreme conditions in Murol. Sam gave a beautiful talk on the study of morphology of organic particles by MAS DNP. We had very lively discussions and lot of fun in a beautiful environment by the lake, surrounded by ancient volcanos.

4/2023: Giulia attended the symposium on spin hyperpolarization in Nottingham

April 2023

Giulia gave an invited talk to the spin hyperpolarization symposium organized by the University of Nottingham. Lots of interesting talks and discussions, food for the mind!

11/2023: New paper from the group

November 2022

Congratulations Marie for this new pedagogical review presenting nuclear magnetic resonance strategies for time-resolved atomic-level investigation of crystallization from solution. There is an interesting section on perspectives and future directions in the field. Non specialists are welcome!

Recent progress in nuclear magnetic resonance strategies for time-resolved atomic-level investigation of crystallization from solution
M. Juramy, G. Mollica*
Current Opinion in Colloid Interface & Science, 63 101663 (2023) 

11/2022: Distinguished Junior Member of the French Chemical Society

November 2022

Another good news! Giulia has been appointed Distinguished Junior Member (Membre Distingué Junior) by the French Chemical Society.

10/2022: New paper from the group

October 2022

We show that additives that serve crystallization can also enhance the sensitivity of DNP.

Monitoring the influence of additives on the crystallization processes of glycine with dynamic nuclear polarization solid-state NMR
M. Juramy, P. Cerreia-Vioglio, F. Ziarelli, S. Viel, P. Thureau, G. Mollica*
Solid-state Nuclear Magnetic Resonance, 122 101836 (2022) 

10/2022: Samuel Cousin is now a permanent CNRS Researcher!

October 2022

Congrats to Sam for successfully passing his CNRS audition. He is now permanent CNRS Researcher!
All the group wishes him lots of success!

4-8/09/2022: The group attended the Alpine Conference on Magnetic Resonance

September 2022

Giulia, Sam and Romain were in Chamonix to attend the Alpine Conference on Magnetic Resonance. Giulia gave a talk on the use of MAS DNP to investigate cristallisation and achieving polymorph selection. Romain and Sam gave two round tables showing recent results on the study of crystallization in inorganic systems and spin diffusion. Awesome conference with very lively formal and informal discussions.

Post-doc in MAS DNP of crystallizing solutions

September 2022

The overall aim of the project is to develop and apply an emerging NMR hyperpolarization technique, namely magic-angle spinning nuclear dynamic polarization (MAS-DNP), to characterize the process of formation of polymorphic organic solids. To apply: https://emploi.cnrs.fr/Offres/CDD/UMR7273-GIUMOL-019/Default.aspx

09/2022: New paper from the group

September 2022

We showed how supercritical CO2 impregnation can be efficiently used to disperse radicals used as polarizing agents for DNP into polymeric materials, enhancing the sensitivity of NMR towards the structural analysis of challenging materials.

Supercritical CO2 impregnation process applied to polymer samples preparation for dynamic nuclear polarization solid-state NMR
D. Le, A. Frison, Y. Masmoudi, A. Bouledjouidja, P. Thureau, G. Mollica, E. Badens, F. Ziarelli, S. Viel
Magnetic Resonance in Chemistry, 60 1171-1177 (2022) 

Supercritical CO2 impregnation process applied to polymer samples preparation for dynamic nuclear polarization solid-state NMR

In this study, supercritical CO2 (scCO2) was used to impregnate polymers with paramagnetic polarizing agents to prepare samples for dynamic nuclear polarization (DNP) solid-state NMR (ssNMR) experiments. As a proof of concept, we impregnated polystyrene samples with bTbK, which stands for bis-TEMPO-bisketal where TEMPO is 2,2,6,6-tetra-methylpiperindin-1-oxyl. Substantial DNP signal enhancements could be measured on DNP-enhanced 1H→13C cross-polarization (CP) magic-angle spinning (MAS) spectra recorded at 9.4 T and ~100 K, reaching a maximum value of 8 in the most favorable case, which appeared comparable or even higher than what is typically obtained on similar systems for former sample preparation methods. These results highlight the potential of scCO2 impregnation as an efficient and possibly versatile methodology to prepare polymer samples for DNP ssNMR investigations.

30/08/2022: PANACEA workshop at EPFL Lausanne

August 2022

Giulia and Romain participated to the PANACEA workshop on ssNMR methods for pharmaceutical formulations hosted by the group of Prof. L. Emsley in EPFL Lausanne. We had a fantastic week of lively discussions between coaches and students in front of the spectrometer and off!

20/07/2022: MoMa Meeting

July 2022

We welcomed the MISOTOP group from the Institut Charles Gerhardt of Montpellier for the third MoMa meeting, where Marie, Samuel and Nghia gave a talk. We had a lot of fun discussing NMR, DNP, isotopic enrichment through mechanochemistry, recoupling methods, spin diffusion and crystallization.

27/05/2022: Giulia gave a talk at HyMar

May 2022

Giulia presented our recent results on the use of MAS DNP for the study of crystallization and selection of polymorph at the online conference HyMar, organized by the Italian discussion group on Magnetic Resonance, GIDRM.

We are happy to have Dr Arthur Pinon with us for two weeks!

May 2022

Dr Arthur Pinon from University of Gothenburg will stay with us for two weeks to work on spin diffusion. Welcome Arthur!

Nghia Duong joined our group as a postdoc, welcome!

March 2022

Nghia is going to work on methodological development in ssNMR and DNP.

Marie's PhD defense

March 2022

Marie successfully defended her PhD on the 4th of March.
Bravo Marie for your hard work, resilience and perseverance, and for a brilliant and living discussion with the jury. Thank you to Anne Lesage and Christian Bonhomme for accepting to review Marie's PhD manuscript and for sharing with us this very happy moment. And thank you to Kenneth Harris and Paul Hogkinson for accepting to be part of the committee.

We are hiring!

January 2022

We are always looking for motivated candidates to join our group. Please contact Giulia Mollica at giulia.mollica@univ-amu.fr for information about currently available positions and projects.

12/2022 New paper form the group

Congratulations to Marie for this very nice review article on NMR and DNP methods for investigating crystallization from solution.

Recent progress in nuclear magnetic resonance strategies for time-resolved atomic-level investigation of crystallization from solution
M. Juramy, G. Mollica*
Current Opinion in Colloid Interface & Science, 63 101663 (2023)