Enhancing Vascularized Bone Regeneration Through Oscillatory Fluid Flow-Regulated Gradient Lattice Gradient Lattice Implants Porous Titanium Alloy.

Abstract

Natural bone has anisotropic mechanical properties. However, most existing 3D printed porous titanium alloy implants are limited by isotropic mechanical behavior and a simple through-hole structure, which cannot fully replicate natural bone structure. This study develops a 3D printed porous titanium alloy scaffold whose truss-based microstructure is designed to simulate the anisotropic characteristics of natural bone. Finite element analysis (FEA) is used to optimize the structural parameters of the scaffold, which enhances the elastic modulus matching with the host bone and improves the cell migration potential. Computational fluid dynamics (CFD) simulations further show that the gradient lattice implant promotes superior fluid dynamics and facilitates interstitial flow in the transport of cellular nutrients. Under oscillating fluid flow (OFF) conditions, bone marrow mesenchymal stem cells (BMSCs) grow along the truss rod with enhanced osteogenic differentiation. BMSCs also promote vascularization through paracrine signaling mechanisms. This bionic scaffold design mitigates the stress shielding effect while optimizing the flow of interstitial fluid to enhance bone regeneration.