The BoneFix team contains a number of young PhD researchers. The training of these students and their successful graduation are among the project’s many expected impacts. The consortium is therefore delighted that on the 14th June Guillaume Patt-Lafitte of MINES Saint-Etienne became the first BoneFix PhD student to successfully defend his thesis, which was titled “Design of a 4D-printed membrane intended as bone fixation patch.” He was supervised by Professor David Eglin.
Guillaume has been instrumental in the evaluation of the contribution the fiber component makes to the mechanical strength of the composite-based fixation patch. The team at KTH had previously shown that the inclusion of a layer of PET-fibre mesh in the composite patch resulted in a small increase in the maximum load withstood by the patch before failure. Guillaume expanded upon this result by investigating how one or multiple layers of the mesh influenced the curing efficiency, strength and durability of the patch as well as looking at the integration of the composite within the pores of the mesh using scanning electron microscopy (SEM). New 4D-printed meshes were then designed using degradable polymers capable of heat-induced shape changes, with the idea being that these meshes could wrap around the surface of the bone to provide extra stability to the fixation. Fused deposition modeling (FDM) was used to print the porous meshes. Different printing patterns were investigated with respect to strength, shape-memory properties and infiltration of the composite within the mesh.
The thesis demonstrates how FDM-based 3D printing can be used to produce degradable 4D membranes with spatially controlled reinforcement and shape-shifting properties. Such membranes have the potential to increase the mechanical competence of composite-based customizable fixations, such as those used in the BoneFix project. The thesis encompassed a wide range of scientific disciplines, from material formulation and mechanical characterization, to the exploration of ex vivo trials. “The most exciting aspect was merging the requirements of clinicians and chemistry, in order to develop new membranes,” explained Guillaume, “particularly through the use of a 4D printing process which is not commonly employed in practical material development.” Guillaume also enjoyed how the project involved collaborations across Europe. Now that the PhD is complete, Guillaume is continuing to work in academic research as a postdoc. We look forward to celebrating other PhD defenses from the BoneFix team in 2025.
Guillaume (3rd from left) on the day of his defense with supervisor Professor David Eglin (left), and members of his evaluation committee Professor Benjamin Nottelet (2nd from left, University of Montpellier) and Assoc. Professor Nathalie Douard (right, MINES)