An Algorithm to Optimize the Micro-Geometrical Dimensions of Scaffolds with Spherical Pores

Abstract

Despite the wide use of scaffolds with spherical pores in the clinical context, no studies are reported in the literature that optimize the micro-architecture dimensions of such scaffolds to maximize the amounts of neo-formed bone. In this study, a mechanobiology-based optimization algorithm was implemented to determine the optimal geometry of scaffolds with spherical pores subjected to both compression and shear loading. We found that these scaffolds are particularly suited to bear shear loads; the amounts of bone predicted to form for this load type are, in fact, larger than those predicted in other scaffold geometries. Knowing the anthropometric characteristics of the patient, one can hypothesize the possible value of load acting on the scaffold that will be implanted and, through the proposed algorithm, determine the optimal dimensions of the scaffold that favor the formation of the largest amounts of bone. The proposed algorithm can guide and support the surgeon in the choice of a “personalized” scaffold that better suits the anthropometric characteristics of the patient, thus allowing to achieve a successful follow-up in the shortest possible time.

Design of Materials for Bone Tissue Scaffolds

“…Many studies have recently been conducted to investigate the optimal manufacturing technologies that can be used to fabricate "smart and custom" scaffolds capable not only of guaranteeing the above-mentioned requirements, but also of satisfying the specific requests of the specific patient in whom it will be implanted [5]. One of the most recent research lines, in fact, has been focused on the design of "personalized" scaffolds that better suit the anthropometric features of the patient, thus allowing to achieve a successful follow-up in the shortest possible time [10]. Different studies have recently been published with the aim of better understanding the relationship between the scaffold geometry/material properties and the consequent mechanobiological phenomena taking place inside the scaffold during the regeneration process.…”

“…Most of the studies of the Special Issue developed innovative materials favoring the formation of new bone in the fracture site where the scaffold is implanted [11][12][13][14][15][16]. Three papers investigate the issues related to the geometry/dimensions that the scaffold pores must possess to guarantee an adequate mechanobiological response [10,17,18]. Finally, three articles deal with more clinical/applicative aspects [19][20][21].…”

“…Very interesting are also the studies investigating the geometry of the scaffold pores, as well as the issues related to the structural response to mechanical loads and the scaffold porosity. Percoco et al [17] and Rodríguez-Montaño et al [10], using the mechanoregulation model by Prendergast et al [22], determined the optimal dimensions that the pores of scaffolds 3D printed with the FDM technique and including spherical pores, respectively, must possess. In this model, the fracture site is modelled as a biphasic poroelastic material, and the biophysical stimulus that triggers the osteogenic differentiation of the mesenchymal stem cells is hypothesized to be a function of the octahedral shear strain and of the interstitial fluid flow measured in the regenerating tissue.…”

“…In this model, the fracture site is modelled as a biphasic poroelastic material, and the biophysical stimulus that triggers the osteogenic differentiation of the mesenchymal stem cells is hypothesized to be a function of the octahedral shear strain and of the interstitial fluid flow measured in the regenerating tissue. The authors, by using this model, defined, via an optimization algorithm, the optimal dimensions of pores for different load values acting on the scaffold [10,17]. Martinez-Marquez et al [18], in their review paper, used the quality by design system to explore the quality target product profile and ideal quality attributes of additively manufactured titanium porous scaffolds for bone regeneration with a biomimetic approach.…”

Characterization and Design Optimization of Periodic Cellular Solids for Optimal Bone Ingrowth in Osseointegration Implants.

“…Another study following the same goal was done to investigate four additional lattice topologies: Truncated Cube, Truncated Cuboctahedron, Rhombic Dodecahedron (with vertical and horizontal orientation), and Diamond [10]. In their last three studies, they investigated irregular load adapted scaffold optimization [10], they compared structures with spherical pores to elliptic and rectangular extrusions [11], and they tried to optimize the distance between the strands in cylindrical scaffolds [12].…”