Computational Fluid Dynamics (CFD) Modeling of Material Transport through Triply Periodic Minimal Surface (TPMS) Scaffolds for Bone Tissue Engineering.

Cell-laden, scaffold-based tissue engineering methods have been successfully utilized for the treatment of bone fractures. In such methods, the rate of scaffold biodegradation, transport of nutrients, and removal of cell metabolic wastes are critical fluid-dynamics factors, affecting tissue regeneration. Therefore, there is a critical need to identify the underlying material transport mechanisms associated with stem cell-driven, scaffold-based bone tissue regeneration. The objective of the work is to establish computational fluid dynamics (CFD) models to identify the consequential mechanisms behind internal and external material transport through/over porous bone scaffolds designed based on the principles of triply periodic minimal surfaces (TPMS). In this study, advanced CFD models were established based on ten TPMS designs for analyzing (i) single-unit internal flow, (ii) single-unit external flow, and (iii) cubic, full-scaffold external flow. The main fluid characteristics influential in bone regeneration, including flow velocity, pressure, and wall shear stress (WSS), were analyzed to assess material transport internally through and externally over the TPMS designs. Schwarz Primitive (P) appeared to have the lowest level of flow pressure and WSS (desirable for development of bone tissues). An analysis of streamline velocity exhibited an increase in velocity togther with a depiction of turbulent motion along the curved surfaces of the TPMS designs. Besides, pressure buildup was observed within the inner channels of almost all the TPMS designs. Overall, the outcomes of this study pave the way for optimal design and fabrication of bone-like tissues with desirable medical properties.