The development of flexoelectricity-based applications is only starting, following important advances in our fundamental understanding of this phenomenon. In the area of biomedical engineering, it has not yet been exploited at all, as the investigation of bioflexoelectricity is in its infancy. Moreover, flexoelectricity in biocompatible materials, a crucial first step for the development of applications, had been scarcely assessed before the start of our project.
The results obtained in this action provide a bridge from the fundamental science to the applications. At the fundamental side, the measurement of the effect of fracture-generated flexoelectricity on bone cells provides a motivation for adding flexoelectricity to osteogenic therapies. At the materials side, our quantification of the flexoelectric properties of biocompatible polymers and composites (PLLA, PCL, their copolymers and composites based on PLLA, PCL and nanoparticles of hydroxyapatite, bioglass) are likely to be a very useful tool for biomedical engineers aiming to introduce flexoelectricity as a design parameter. This action has identified a few compositions of the above mentioned polymers and composites that have the ability to generate flexoelectric field theoretically large enough to stimulate cells.
One of the most interesting aspect of flexoelectricity is the possibility to design non-piezoelectric materials to exhibit piezoelectric-like properties by clever texture-engineering at the microscale. Our results show that this can be achieved using the right compositions in devices with in-built strain gradients, e.g. polymeric scaffolds with porosity gradients where the texturization generates large strain gradients. While the project has fallen short of producing an actual flexoelectric bone prosthesis, it has laid the foundations (fundamentals, materials, design parameters) for this to be achieved.
