The finite element method was applied to determine the mechanical performance of different TPMS lattices at different relative densities inside the SPS under a three-point bending test, and the results were compared with the values calculated from analytical equations. The types of TPMS lattices considered included the Schwarz primitive (SP), Scherk’s surface type 2 (S2), Schoen I-graph-wrapped package (I-WP), and Schoen face-centred cubic rhombic dodecahedron (F-RD). Each SPS comprised two face sheets and a core filled with 20×5×1 TPMS lattices. In this study, the different types of TPMS lattices inside an SPS were analysed comprehensively. Compared with extruded lattice types, triply periodic minimal surface (TPMS) lattices have light weight but better controllable mechanical properties. Sandwich panel structures (SPSs) with lattice cores can considerably lower material consumption while simultaneously maintaining adequate mechanical properties. Finally, examples of 3D-printed biomaterials with tuned properties and functionalities are presented. Recent developments related to the biomedical applications and fabrication methods of AM aimed at enhancing the quality of final 3D-printed biomaterials and improving their physical, mechanical, and biological characteristics are also highlighted. The design strategies can be categorised as: library-based design, topology optimisation, bio-inspired design, and meta-biomaterials. In this review article, we provide an overview of the design principles that have been developed and used for the AM of biomaterials as well as those dealing with three major categories of biomaterials, i.e., metals (and their alloys), polymers, and ceramics. Meanwhile, the capabilities of AM to fabricate a wide range of biomaterials, including metals and their alloys, polymers, and ceramics, have been exploited, offering unprecedented benefits to medical professionals and patients alike. In the past few decades, several design guidelines have been proposed for creating porous lattice structures, particularly for biomedical applications.

Īdditive manufacturing (AM, also known as 3D printing) is an advanced manufacturing technique that has enabled progress in the design and fabrication of customised or patient-specific (meta-)biomaterials and biomedical devices (e.g., implants, prosthetics, and orthotics) with complex internal microstructures and tuneable properties. In this study, we consider pri- marily the design elements pertaining to a scaffold formation and changes in its geometrical. It is noted that for truly functional bone scaffolds, considera- tion of the load bearing and stiffness characteristics would be required in working circumstances. For example, in tissue engineering, it may be desirable to have a configuration with large surface area and relatively low scaffold interconnect thickness to maximize surfaces for cellular adhesion and growth, while providing optimal permeability through the bulk of the scaf- fold. Both configurations offer unique geometrical attributes to the overall resulting scaffold structure in terms of sur- face to volume ratios and scaffold interconnect thickness, which can then be tailored to a respective application. Figure 1(b) illustrates the boundary condition in the x, y, and z directions to adjust the unit cell from surface to branching configurations. 1(a)-(iv)-(vi)), which we will refer to as branching unit cells. How- ever, by adjusting the boundary conditions, these functions can also be converted into a configuration with a more 'branch' type geometry ( Fig.

1(a)- (i)-(iii)), which we will refer to as surface type unit cells.

of the selected triply periodic functions is commonly known to realize complex continuous surface profiles ( Fig.

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