Geometry modelling of regular scaffolds for bone tissue engineering: A computational mechanobiological approach

Scaffolds are porous biomaterials that serve to replace missing portions of bone. Scaffolds must possess a proper geometry and hence have to be adequately designed to correctly undergo to the load and to favor the differentiation of the mesenchymal stem cells invading it, into osteoblasts. It is commonly known that scaffold geometry affects the quality of the regenerated bone creating within the scaffold pores. Scaffold properly designed trigger favorable values of biophysical stimuli that are responsible for the reactions cascade leading to the bone formation. In this paper an optimization algorithm is proposed that, based on mechano-regulation criteria, identifies the optimal geometry of scaffolds, i.e. the geometry that favors the formation of the largest amounts of bone in the shortest time. In detail, the algorithm, written in the Matlab environment, incorporates parametric finite element models of different scaffold types, a computational mechanobiological model and structural optimization routines. The scaffold geometry is iteratively perturbed by the algorithm until the optimal geometry is computed, i.e. the geometry that triggers the most favorable values of the biophysical stimulus which lead to the formation of mature bone. Mesenchymal stem cells were hypothesized to spread within the fracture domain and uniformly occupy the scaffold pores.