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Sujet de stage / Master 2 Internship

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Development of NMR methods for the analysis of complex mixtures using parahydrogen

Contact: HUBER Gaspard, , gaspard.huber@cea.fr, +33 1 69 08 64 82
Summary:
Metabolomics is the science that relates to the analysis of metabolites, the small molecules (less than 1500 Da) present in organisms. It helps to understand the functioning of these organisms, and to detect, identify or even quantify metabolites that sign a given pathological state or a stress. Nuclear Magnetic Resonance (NMR) is a complementary technique to mass spectrometry (MS) to analyze complex mixtures of metabolites. However, despite its robustness and quantitative character, and because of its low sensitivity, NMR is not used as much as MS. One of them takes advantage of the special properties of parahydrogen, a spin isomer of dihydrogen gas.
The thesis consists in developing the methodology of the SABRE-Relay method when it is applied to cellular metabolic extracts or to biofluids.

The internship and the thesis will involve instrumental developments (fluidics, rapid sample motions).The objective is to propose new metabolic profiles, offering a greater sensitivity and specificity, compared to conventional profiles by NMR, for a better detection, identification or even quantification of the metabolites. We are collaborating with another CEA-Saclay laboratory, LEMM, specialized in metabolomics by mass spectrometry.
Possibility of continuation in PhD: Oui
Deadline for application:04/03/2022

Full description:
Context and research project:

Metabolomics aims to characterize the "small molecules" (<1500 Da) of a biological sample. It is based mainly on high resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR). These two techniques are complementary. LC-HRMS analysis is very sensitive and can detect thousands of signals at concentrations down to nanomolar, but it is not very reproducible. NMR is robust and quantitative, but only allows the detection of the most abundant metabolites due to its lack of sensitivity. In addition, NMR and HRMS are complementary in terms of molecular identification, NMR providing information at the local scale, while HRMS provides more global information.

Parahydrogen is one of the methods known to drastically but temporarily increase the sensitivity of NMR. LSDRM has developed an apparatus aiming at enriching dihydrogen in parahydrogen. LSDRM also developed NMR and instrumental developments for parahydrogen application [1]. Characteristic signals of some molecules are increased by means of a method called SABRE [2]. Recently the range of molecules sensitive to the method, so far quite restricted, has been extended to molecules possessing at least one exchangeable proton, a method called SABRE-Relay [3].
The Master 2 research project aims to explore the SABRE and SABRE-Relay methods for the identification of urinary metabolites. The subject involves instrumental developments intended to quickly moving fluids (gases or liquids) in the detection zone of the NMR spectrometer. The results will then be compared with those obtained elsewhere by HRMS on similar samples for identification assistance.

Work environment:

The Master 2 internship will take place at the Structure and Dynamics by Magnetic Resonance Laboratory (LSDRM) of CEA-Saclay, 25 kms South-West of Paris, in collaboration with the Drug Metabolism Research Laboratory (LEMM),also at CEA-Saclay. The internship is part of a larger study combining metabolomic analyzes based on NMR and HRMS.
LSDRM is an expert in developing novel approaches to magnetic resonance spectroscopy. In particular, LSDRM is developing methods aimed at increasing the sensitivity of NMR. It is equipped with 6 NMR spectrometers from 1.0 to 11.7 T. LEMM has specialized in metabolomic analysis since 2002, thus accumulating expertise in terms of development and validation of LC-MS methods for profiling biofluids and tissue and cell extracts.

Candidate profile and application:
Engineer and / or M2 student in physics, physico-chemistry or chemistry. Specialization in analytical chemistry or physico-chemistry with an interest in NMR, instrumentation and experimental sciences. Desired internship start date: February 2022. Applications (CV and cover letter) should be sent to gaspard.huber@cea.fr .

References:
[1] Guduff et al. Single-Scan Diffusion-Ordered NMR Spectroscopy of SABRE-Hyperpolarized Mixtures. ChemPhysChem 2019, 20, 392–398.
[2] Sellies et al. Parahydrogen induced hyperpolarization provides a tool for NMR metabolomics at nanomolar concentrations. ChemComm 2019, 55, 7235-7238.
[3] Iali et al. Using parahydrogen to hyperpolarize amines, amides, carboxylic acids, alcohols, phosphates, and carbonates. Sci. Adv. 2018; 4 : eaao6250
Technics/methods used during the internship:
NMR

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