BONEREPAIR · Using electromechanical stimulations on bone remodeling to speed-up repair bone damage

Osteoporosis is a major concern in Europe, resulting in 4.3 million fragility fractures and health care costs in excess of €56 billion annually. Bone, a smart material, can detect microcracks or microdamages and to repair these microdefects due to its growth and remodeling capabilities in the presence of electro-mechanical stimuli. Dry and wet bone involve matrix piezoelectricity, namely a coupling between deformation and polarization. Flexoelectricity, the phenomenon coupling deformation gradients and polarization, still presents experimental and theoretical challenges.Bone biomechanics has been resistant to progress due to the complexity of the propagation of information across the scales of the bone hierarchical microstructure and the multidisciplinary nature of bone biomechanics. BONEREPAIR has the potential to provide a global vision of the effects of electro-mechanical signals on bone remodeling and healing, from the cellular to tissue level, by: 1) Characterizing the response of bone to electro-mechanical stimuli, from cellular to tissue level, via dedicated experiments on biomaterials and bone explants based on novel Bone-on-Chip systems, 2) Modelling the bone cells' response to electro-mechanical stimuli and their gradients, and incorporate them into a unified field theory of bone remodeling and healing, and 3) Designing adequate electro-mechanical stimuli promoting bone healing more efficiently. We hypothesize it is possible to heal bone by applying well-calibrated electro-mechanical stimuli, from the cellular level up to the tissue level, by using multiscale methods to upscale electro-chemo-mechanical phenomena – including piezoelectricity, flexoelectricity, and damage – from microcrack scale up to the tissue level. BONEREPAIR will moreover largely contribute to the development of novel homogenization methods towards generalized continua for composite materials showing multiphysical behavior like piezoelectricity and flexoelectricity.