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Reference : UMR5248-MARDUR-001
Workplace : PESSAC
Date of publication : Monday, July 19, 2021
Scientific Responsible name : DURRIEU Marie-Christine
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 November 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Stem Cells (SCs) are involved in the structuration or regeneration of all tissues of the body and have numerous foreseen applications in tissue engineering. Mesenchymal stem cells (MSC), present in very small quantities in adults, are multipotent cells which are an important source for cell therapy and tissue engineering applications and which could be involved in the restoration of specific tissues and organs such as cartilage cells (chondrocytes), bone cells (osteoblasts), fat cells (adipocytes) or muscle cells (myocytes). Thus, the recent advances in tissue engineering and regenerative medicine are based on several protocols inducing ex vivo stem cell differentiation before in vivo transplantation. But to obtain tissues or organoids, a main drawback is the ex vivo production of clinically relevant quantities of differentiated functional cells. Indeed, the lack of abundant sources of MSC and efficiency of their differentiation make difficult to obtain enough cells to move forward to further steps. It has been shown that the stem cell microenvironments (biochemical, topographical or mechanical features) impact on the cell differentiation yield and determine important aspects of their physiology. No current system can satisfactorily deliver a strategy to envision the fabrication of an innovative coating (a smart cell culture plate) for the rapid production at high yields of osteoblast cells from hMSC of a patient. Today, it is indeed currently not possible to control at 100% the differentiation of MSC towards a desired lineage. As such drawbacks currently limit the therapeutic potential of 2D-cultured MSCs, alternative culture methods have been investigated to best preserve the cells' progenitor properties, and this has emerged as one of the most important topics in MSC research. There is growing interest in culturing adherent cells which best reproduce in vivo conditions. Natural or synthetic polymers have long been used as a coating in cell culture components and it also recently became apparent that dendritic structures could also be tested in cell culture. From this point of view, dendritic polymers fully made up of essential amino acids, such as Dendri-Graft of Lysines (DGL), seem to be of primary interest. They are “tree-like” polymers of L-lysine or D-Lysine, 100% biocompatible, non-immunogenic, water-soluble and stable. They can be shaped into hybrid scaffolds by incorporating in a covalent way a variety of biological and/or chemical substances to actively support the material microenvironment during cell growth and to induce a determined response from the surrounding environment. The aim of our project is to discuss how density or distribution of bioactive principles, and how the mechanical properties of DGLs could potentiate the in vitro differentiation of MSCs into an osteogenic lineage. To achieve this objective, this project will progress by a multidisciplinary approach (from the synthesis of dendrimers to the in vitro cell culture tests) with interconnected WPs (in collaboration with a company in montpellier (France). We propose to use the properties of various generations of native or customized DGL (Poly-L or D-Lysines DendriGrafts) as biocompatible stimulating interfaces presenting various controlled mechanical properties to favour MSC adhesion, differentiation. The synthesis, customization and immobilization onto a cell culture plate of various DGLs generations will be performed so as to embed active principles in order to guide the MSC adhesion and differentiation. The mechanical properties of hydrogel will be investigated by Atomic Force Microscopy.
This multidisciplinary collaborative research project involves 2 partners with complementary expertises (one company and one academic laboratory): The academic laboratory (CBMN at Bordeaux University) is internationally recognized for their skill in materials surface functionalization, micro-, nanostructuration through mainly top-down approaches, studying cell-material interactions (cell adhesion and differentiation) and AFM. The company FGHI develops polymer's architectures based on proteinogenic amino acids. Dr Durrieu from CBMN and Dr Granier from FGHI have already collaborated closely for more than 2 years on all preliminary work.
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