A multiscale optimisation method for bone growth scaffolds based on triply periodic minimal surfaces

Abstract

Tissue engineered bone scaffolds are potential alternatives to bone allografts and autografts. Porous scaffolds based on triply periodic minimal surfaces (TPMS) are good candidates for tissue growth because they offer high surface-to-volume ratio, have tailorable stiffness, and can be easily fabricated by additive manufacturing. However, the range of TPMS scaffold types is extensive, and it is not yet clear which type provides the fastest cell or tissue growth while being sufficiently stiff to act as a bone graft. Nor is there currently an established methodology for TPMS bone scaffold design which can be quickly adopted by medical designers or biologists designing implants. In this study, we examine six TPMS scaffold types for use as tissue growth scaffolds and propose a general methodology to optimise their geometry. At the macro-scale, the optimisation routine ensures a scaffold stiffness within suitable limits for bone, while at the micro-scale it maximises the cell growth rate. The optimisation procedure also ensures the scaffold pores are of sufficient diameter to allow oxygen and nutrient delivery via capillaries. Of the examined TPMS structures, the Lidinoid and Split P cell types provide the greatest cell growth rates and are therefore the best candidates for bone scaffolds.

Definition, measurement, and function of pore structure dimensions of bioengineered porous bone tissue materials based on additive manufacturing: A review

“…The first one defines the maximum 3D space dimension that can be accommodated within the smallest pore structure within the porous material as the pore size. Then it defines the maximum 2D plane dimension that interconnects the pore structure inside the porous material with other adjacent pore structures as the pore throat size, as shown in Figure 2A ( Afshar et al, 2016 ; Jette et al, 2018 ; Ambu and Morabito, 2019 ; Wang et al, 2020 ; Lehder et al, 2021 ; Timercan et al, 2021 ). The second one defines the maximum 2D plane dimension of the pore within the porous material that interconnects with other adjacent pore structures as the pore diameter.…”

“…The ability of these materials to promote bone tissue repair and reconstruction has been widely recognized ( Xia et al, 2023 ; Dall'Ava et al, 2020 ; Chen et al, 2018 ). The bioengineered porous bone tissue materials promote bone tissue reconstruction and repair by providing an effective support effect and maintaining a good mechanical environment at the defect site after implantation ( Ponader et al, 2010 ; Wang et al, 2020 ; Lehder et al, 2021 ). They also act as a scaffold for tissue growth, enabling the growth and formation of fibers, blood vessels, and bone tissue ( Harrison et al, 2014 ; Taniguchi et al, 2016 ; Wu et al, 2022 ).…”

Design and performance analysis of 3D-printed stiffness gradient femoral scaffold

“…Mehta et al [ 14 ] showed that the strain of about 1% in the early stage of bone healing is conducive to the growth of bone tissue. For the repair of load-bearing bone defects, the traditional method is to use porous scaffolds whose mechanical properties match the bone tissue for repair [ 15 ]. To achieve the strain window described above, scaffolds that are softer than bone tissue should be used at the site of bone defect.…”

Study on Performance Simulation of Vascular-like Flow Channel Model Based on TPMS Structure

“…As a pore-forming unit, TPMS can realize the digital representation of a porous structure. There are also advantages to the porous structures found in capillaries, such as diffusion of nutrients and small pore size limitations [ 15 ]. Davar Ali investigated the effect of TPMS scaffold structures on cell adhesion during the diffusion of nutrient delivery in culture media [ 16 ].…”