Mechanical and Biological Characterization of 3D Printed Lattices

Abstract

3D printing enables the manufacturing of complex structures with favorable properties for diverse applications. Here, we investigate 3D printed polymer lattices for tissue engineering, with the exemplary application of a spinal fusion cage. Four beam-based topologies with cubic unit cells were designed with specified beam diameters, porosities, and pore sizes. Measured porosities were generally higher than designed, with a maximum mean difference of 0.08. Measured elastic moduli increased for lattices with fixed porosity when beam diameter was increased and decreased for lattices with fixed beam diameter when porosity was increased. In vitro biocompatibility, cell adhesion, and tissue growth were demonstrated in lattices designed with 500 and 1000 μm pores of varied geometries. Spinal cage designs were fabricated with suitable properties for bone fusion, including 50% porous unit cells, 600-μm-sized pores, and up to 5.6 kN/mm stiffness. The study demonstrates the feasibility of polyjet printed scaffolds for tissue engineering and highlights the capabilities of 3D printed lattices for diverse applications.