Multiscale Models of Degradation and Healing of Bone Tissue Engineering Nanocomposite Scaffolds

Abstract

Biomaterials selection and design, and mechanical properties evolution during degradation and tissue regeneration play a critical role in the successful design of nanocomposite scaffolds for bone tissue regeneration. A new multiscale mechanics-based in silico approach is developed to provide a robust predictive methodology for nanocomposite scaffolds. Scaffolds are fabricated using amino acid–modified nanoclay with biomineralized hydroxyapatite (in situ HAPclay) and polycaprolactone (PCL). Steered molecular dynamics (SMD) simulations of the molecular models of HAPclay and the PCL composite provide a mechanical response of the material and the nature of the molecular interactions among constituents. The mechanical responses obtained from SMD are incorporated into a finite element (FE) model of a PCL/in situ HAPclay scaffold with its microstructure obtained from microcomputed tomography images. The model is validated using experimental results. The stress–strain response from multiscale models and experiments shows good agreement with the consideration of wall porosity correction. The multiscale models incorporate damage mechanics–based degradation and healing behavior to capture the evolution of the mechanical properties as the scaffolds degrade and human osteoblasts grow and proliferate inside the scaffolds. The novel multiscale models provide a robust prediction of the mechanical properties evolution in the scaffolds over the time evolution of cell growth proliferation and tissue formation.