Jean-Lynce GNANAGO defended his PhD on April 7th, 2023 at 02:00PM.
Place : conference room of the Library of Université Lyon 1, 69100 Villeurbanne
Jury :
Rapporteurs :
Mme. Elodie PARZY, Maîtresse de Conférences HdR au CRMSB, Université de Bordeaux
M. Jean-Christophe GINEFRI, Maître de Conférences HdR au BIOMAPS, Université Paris-Saclay
Examinateurs :
Mme Marie FRENEA-ROBIN, Professeure des Universités à Ampère, Université Lyon1
Mme Gaelle LISSORGUE, Professeure des Universités à l’ESYCOM, Université Gustave Eiffel
M. Bruno QUESSON, Directeur de Recherches au CRCTB, Université de Bordeaux
Encadrement à Ampère:
M. Simon LAMBERT, Maître de Conférences HdR, directeur de thèse
M. Michel CABRERA, Directeur de recherches, co-Directeur de thèse
Abstract :
Over the last two decades, the comparison between 2D and 3D cell culture has shown that the latter is the cell culture method that most closely reproduces the in vivo physiological environment. 3D cell culture has therefore rapidly become an established part of biology research. From the point of view of characterisation, the generalisation of 3D cell culture poses new challenges. In fact, the optical modality, commonly used in 2D cell culture, does not allow the characterisation of thick soft tissues in 3D due to its poor penetration depth. This problem extends to ex vivo soft tissues of animal models, so an equivalent to optical imaging but applicable to thick opaque 3D soft tissues is required.
MRI has emerged as the modality of choice for such 3D characterisations due to its non-invasive, non-ionising, multi-scale and multi-parameter characterisations. MRI is a commonly used clinical modality but suffers from a high degree of complexity that reserves it for experienced users. In addition, clinical MRI devices are unsuitable for 3D characterisation of thick, live soft tissue soft tissues kept alive. In addition, the dimensions of the structures of interest in 3D cell culture or in small animal models motivate 3D characterisations with spatial resolutions of the order of a few hundreds of μm. The design of a device allowing 3D MRI characterisation of soft tissues in vitro/ex vivo kept alive at resolutions below a hundred μm would therefore constitute an important step in the development of cell culture.
To achieve this, the use of an innovative manufacturing method called “3D Plastronics” is favoured. “3D Plastronics” allows the integration of ’electronic’ functions into the 3D surface of an object. The 3D Plastronics method allows the integration of electronic functions into the 3D surface of a shaped polymer. This fabrication method also allows the integration of functions in the volume of the polymer, thus allowing the creation of functional sensors with complex shapes adaptable to several types of applications.
The aim of this thesis is to illustrate the possibilities offered by 3D plastronics for the design and realisation of a 3D MRI characterisation device combining live tissue conditioning and an integrated MRI antenna dedicated to MRI microscopy. This device is called an “MRI enclosure”. The first step was to evaluate the performance of the MRI enclosure in comparison with devices produced by conventional manufacturing methods. In terms of noise figure, the 3D plastronic MRI antenna is comparable to FR- 4 substrate antennas. The integration of the MRI antenna within the MRI enclosure shows a degradation of the noise figure by a few dozen percents. This integration therefore constitutes a work axis for the optimisation of the performance of the MRI enclosure.
In the second part of the study, the bench-top characterisations showed an improvement in the signal-to-noise ratio of up to a factor of 10 compared to commercial experimental devices allowing the same type of characterisations. In addition, the integration of additional functions such as a mechanical actuator for elastography and a fluidic circuit for the supply of nutrients necessary for 3D cell culture is studied in this thesis.
Finally, the application of the MRI enclosure as a tool for 3D morphological characterisation of a chicken embryo is presented. In addition, the monitoring of the development of a tumour model through the measurement of the apparent diffusion coefficient is also presented.
Keywords:
Magnetic Resonance Imaging, Plastronics, Tissue engineering, 3D Printing