SiCxNy:H thin films are obtained with the microwave plasma assisted chemical vapour deposition (MPACVD) method in the gas mixture H2/Ar/Hexamethyldisilazane. When very few amounts of nitrogen are added to the gas mixture, the film composition changes drastically from SiCx:H like films to SiNx:H like films, according to X‐rays Photoelectron Spectroscopy and Fourier Transform Infra‐Red Spectroscopy (FTIR) analysis. The refractive index (n) and Tauc's optical gap (Eg) are modified over a wide range of values (1.75 ≤ n ≤ 2.15 and 3.5 eV ≤ Eg ≤ 5 eV) with nitrogen addition to the feed gas leading to thin films optical constants close to those of SiC or Si3N4. Therefore, for the films obtained without nitrogen, SiC nanoparticles with a size of about 20 nm embedded in an amorphous SiCN:H matrix are synthesized, leading to nanocomposite films.

Bioengineering has become one of the most promising fields in regenerative medicine. Many of its applications have been settled through stem cell research in order to develop innovative stimuli to differentiate the cells into a specific lineage via physical stimulation such as thermal, mechanical or electrical stimuli to avoid the use of biochemical products. Many examples are found in literature], however none of them could provide conclusive answers in this research field. Piezoelectric materials are able to combine mechanical and electrical stimulation. Environments mimicking in vivo conditions are supposed to be the best to induce differentiation process, but these mechanisms are still not fully mastered and very much dependent on cell type.In this poster, we will introduce the experimental setup used to study the effects of physical (i.e. electrical and/or mechanical) stimulation on human mesenchymal stem cells. An overview of the thought process leading to our project is exposed, as well as a brief bibliographical study of electrical stimulation effects on cells. The emphasis will be focused on the piezoelectric materials used in this project. We selected a nanocomposite material, a copolymer P(VDF-TrFE) matrix charged with ZnO nanoparticles, in order to modulate the mechanical and piezoelectric properties of the matrix as well as to provide a better sticking surface favouring cell adhesion.