Danielle Laurencin is a CNRS researcher at the Institut Charles Gerhardt in Montpellier (France). Her research activities are at the interface between materials chemistry and solid state Nuclear Magnetic Resonance (NMR), with a particular focus on (i) calcium phosphate materials (including hydroxyapatite and bone), (ii) organic-inorganic hybrid materials (involving in particular organoboron molecules like boronic acids and benzoxaboroles), and (iii) solid state NMR of alkaline earth metals (especially calcium-43). More recently, she has also started to look into the use of mechanochemistry as a new means of labeling organic and inorganic compounds of synthetic interest in oxygen-17, in view of 17O solid state NMR analyses.
Danielle received her PhD in 2006 from the University Pierre et Marie Curie (Paris, France) in the field of inorganic molecular chemistry (functionalization of polyoxometalates for catalytic applications). Then, she was awarded a Marie-Curie fellowship to perform a 2-year post-doc at the University of Warwick (UK), during which she worked on apatite-related biomaterials and more specifically on their characterization by solid state NMR. She was then recruited at the CNRS in 2009, and passed her habilitation in 2015.
Danielle is co-author of over 70 peer-reviewed international publications and 1 patent. She has given more than 15 invited presentations in international conferences and workshops, as well as over 50 other talks on her work. Since 2007, she has been successful in obtaining funding at the national (ANR, Labex ChemiSYST), European (Marie Curie IEF; Marie Curie ERG; ERC Consolidator grant) and international (PUF) levels to develop her research projects. In 2013, she was awarded the CNRS Bronze medal, which is the highest distinction given by the CNRS to the most promising young researchers in France.
Nuclear Magnetic Resonance (NMR) spectroscopy has emerged over the years as an invaluable technique for studying the atomic-level structure of a variety of biological systems, ranging from membrane proteins and viruses to tissues like bone. While high resolution 1H, 13C, 15N and 31P NMR experiments have been mainly used for this purpose, other essential nuclei like oxygen and calcium have been left out of most investigations. This is mainly due to the unfavorable properties of the corresponding NMR-active isotopes, oxygen-17 and calcium-43, which are both poorly-receptive quadrupolar nuclei. Indeed, 43Ca is a spin-7/2 isotope of low natural abundance (0.14%) and very low resonance frequency (ν0 ~ 40 MHz on a 600 MHz NMR spectrometer), while 17O is a spin-5/2 isotope of very low natural abundance (0.04%) and low resonance frequency (ν0 ~ 81 MHz on a 600 MHz NMR spectrometer).
Although calcium-43 and oxygen-17 are still generally considered as “exotic” nuclei for NMR spectroscopy, several recent advances are making their analysis by solid state NMR become not only more accessible but also more informative. Here, our latest contributions along these lines will be presented, which include (i) new labeling schemes for the preparation of 17O-enriched compounds; (ii) high-resolution experiments for 43Ca (including 43Ca…1H and 43Ca…13C correlation experiments), and (iii) natural abundance 43Ca NMR studies performed at ultra-high magnetic fields (35 T) or using dynamic nuclear polarization (DNP). To illustrate these points, spectra of both natural and synthetic materials will be presented, with the idea of showing the level of structural insight that can currently be reached. The compounds discussed will include substituted hydroxyapatites (which are related to bone and teeth), calcium pyrophosphates (which are related to the pathological calcifications involved in a disease called “pseudo-gout”), and calcium oxalates (which are related to kidney stones).