Development of correlative multimodal imaging using hard-soft-X-ray-and-uv-synchrotron-radiation for structural cell biology at the Mesoscale

Supervisor Organisation PhD Awarding Entity: phd location
Synchrotron Soleil
Paris Saclay University
Synchrotron Soleil, Saclay, France

Research Focus

Nowadays cell biology requires to correlate high resolution morphology and chemical information to apprehend the complexity of the inner cellular organisation of living systems.

In order to efficiently get insightful information to address challenging scientific questions using efficient correlative imaging approaches, careful and innovative sample preparations and validations are mandatory. In this context, the SOLEIL health and biology scientific section, hosted by a large facility, benefits from in-house pilot projects and a large network of synchrotron users and collaborators for developing a wide panel of live and cryo-correlative imaging projects. These unique beamlines portfolio allow combining biophysics and imaging methods for Correlative Light Electron and X-ray Microscopy as proposed in CLEXM doctoral network initiative.

The project will focus on tailored sample preparations and standard qualification for a large diversity of scientific topics in cell biology.

Methodology

The SOLEIL facility provides a wide range of photons energies, from IR to Hard X-ray coupled with state-of-the-art beamlines that cooperate to combine imaging and X-ray diffraction modalities. In addition, SOLEIL will host a 300kV cryo-EM early 2024. Proper biological sample (such as bacteria, eukaryotic cells to mono- or multicellular layers and tissues) cryo-preparation is critical for successful and relevant correlative bio imaging experiments.

It relies on the double objective that the biological sample layered on the sample holder (typically a cryoEM grid or a silicon nitride film for example) will be preserved in its physiologically relevant state while ensuring multimodal data acquisition. Sample thickness and distribution within thin vitreous (non-crystalline) water are critical parameters for successful CLEXM approaches. Therefore, proper evaluation of these sample characteristics is mandatory for sample preparation workflows validation using an innovative combination of techniques available at SOLEIL.

SOLEIL also hosts microfluidics assisted live imaging instruments (VUV beamline, multiphoton microscope) that will provide opportunities to develop original methods to link dynamics (live microscopy) and high spatial resolution (cryo-microscopy) information on biological systems.

Aim 1

Thick biological sample preparation for imaging (eukaryotic cells, tissues…)

Aim 2

Hard X-rays to characterize vitrification processes
(Diffraction patterns)

Aim 3

Hard X-rays fluorescence: elemental mapping & Common multi-technique grid cryo-holder design

Pictures Attached

Image description: Synchrotron Soleli

PhD Researcher

Name: Harisa Rista

University: Paris Saclay University

Supervisor’s Name: Dr. Frederic Jamme/Dr. Pierre Montaville/Dr. Pierre LeGrand

Harisa Rista completed her Bachelor’s and Master’s degrees in Physics at the University of Camerino. The undergraduate program, with a focus on Nuclear Physics, laid the foundation for an in-depth exploration of X-ray interactions with organic matter during her Master’s studies. As a guest of the University of Antwerp, at the Biophysics section of the Physics department, during her ERASMUS semester, she conducted research on X-ray-induced radicals in carbohydrates using various EPR spectroscopic techniques. As an experimental physicist, she acquired a versatile skill set encompassing a wide range of spectroscopic techniques, including XRF, XPS, and Raman. Harisa is now poised to pursue a Ph.D. at the SOLEIL Synchrotron within the CLEXM Consortium, where she will gain expertise in cryo sample preparation and imaging methods for Correlative Light, Electron, and X-ray Microscopy.

She is fascinated by the complexity of biological systems, and she wishes to use her background in Physics to place herself and her research at the interface between these two worlds. The overarching goal of her research is to elaborate and develop optimized cryo-sample preparation workflows and methodologies for already existing as well as innovative correlative bioimaging approaches for cell biology. The resources and collaborative opportunities within the SOLEIL health and biology scientific section will allow her to thrive as a researcher and contribute to the collective efforts of the CLEXM project.

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