Design and Analysis of Biomedical Scaffolds Using TPMS-Based Porous Structures Inspired from Additive Manufacturing

Abstract

Gyroid (G) and primitive (P) porous structures have multiple application areas, ranging from thermal to mechanical, and fall in the complex triply periodic minimal surface (TPMS) category. Such intricate bioinspired constructs are gaining attention because they meet both biological and mechanical requirements for osseous reconstruction. The study aimed to develop G and P structures with varying porosity levels from 40% to 80% by modulating the strut thickness to proportionally resemble the stiffness of host tissue. The performance characteristics were evaluated using Ti6Al4V and important relationships between feature dimension, strut thickness, porosity, and stiffness were established. Numerical results showed that the studied porous structures could decrease stiffness from 107 GPa (stiffness of Ti6Al4V) to the range between 4.21 GPa to 29.63 GPa of varying porosities, which matches the human bone stiffness range. Furthermore, using this foundation, a subject-specific scaffold (made of P unit cells with an 80% porosity) was developed to reconstruct segmental bone defect (SBD) of the human femur, demonstrating a significant decrease in the stress shielding effect. Stress transfer on the bone surrounded by a P scaffold was compared with a solid implant which showed a net increase of stress transfer of 76% with the use of P scaffold. In the conclusion, future concerns and recommendations are suggested.

In-Silico Prediction of Mechanical Behaviour of Uniform Gyroid Scaffolds Affected by Its Design Parameters for Bone Tissue Engineering Applications

“…It was calculated that the effective elastic modulus of the gyroid structure was 3.565 GPa, matching the properties of a trabecular bone [58]. Verma et al again designed gyroid-based Ti6Al4V scaffolds with a range of porosities from 40% to 80% and found that the range of effective elastic modulus of 7.16 to 29.63 GPa is favourable for cortical bone implants [59]. Peng et al designed anisotropic gyroid cellular structures of titanium alloys and applied FEM to find their elastic responses under compressive loading.…”

Computational Modelling and Simulation of Scaffolds for Bone Tissue Engineering

“…Verma et al [93] utilised a non-linear isotropic hardening elastoplastic model for FE simulations involving diverse compressive loading scenarios. These simulations focused on a Ti6Al4V primitive (P) TPMS scaffold with 80% porosity fixed within a segmental In bilinear isotropic (BISO) hardening models, the stress and strain vary even after attaining maximum plastic deformation.…”

Experimental investigation of mechanical properties and energy absorption capabilities of hybrid lattice structures manufactured using fused filament fabrication

“…These advantages recently expanded the applications of lattice structures and now they are used in advanced fields like aerospace, automotive, and biomedical. In biomedical engineering, lattice structures with tailored mechanical properties are used for the manufacturing of the porous implants [4][5][6][7][8][9]. By controlling the mechanical properties, it is possible to customize the stiffness of the implant, which may be equal to that of the bone, and avoid stress shielding [5].…”