A Computational Based Design and Optimization Study of Scaffold Architectures

Abstract

Printed and reproducible scaffolds with regular structures are receiving an increased interest in tissue engineering since they offer greater control of the scaffold porosity, and pore size, and better prediction of the fluid flow inside the scaffold. One of the most important factors that must be examined before the construction of a scaffold for experimental use is the shear stress, which depends strongly on the geometrical characteristics of the scaffold. In this work, computational fluid dynamics (CFD) simulations are carried out for four different scaffold architectures and various porosities and pore sizes. The calculated shear stresses are used for investigating the relation between the shear stress and the scaffold architecture, the scaffold design parameters and the Darcian permeability factor. It is found that for each scaffold model there is a critical porosity and a critical permeability factor below which the shear stress increases significantly, leading to the conclusion that such design parameters must be avoided for effective cultivation.

Irregular Load Adapted Scaffold Optimization: A Computational Framework Based on Mechanobiological Criteria

“…The algorithm reads the text file and copies and pastes the coordinates and the connectivity into a Python Script (PS1) (Figure 10, block [4]). A candidate solution of the diameter D is then initialized by the user (Figure 10, block [5]) and entered into the same python script PS1 (Figure 10, block [6]), which is, in turn, given in input to Rhinoceros (Figure 10, block [7]). Rhinoceros "dresses" the skeletonized structure with a 3D solid model including cylindrical elements with the diameter D equal to that initialized by the user and spherical elements with diameter D S = 1.1 × D (Figure 10, block [8]).…”

“…Once this occurs, the optimization process stops (Figure 10, block [19]) and the algorithm gives in output both the optimal value of D and the corresponding amount of bone BO %max . On the contrary, if the stopping criteria are not satisfied, the algorithm iteratively perturbs the dimension of the diameter D (Figure 10, block [20]) and selects new candidate solutions (Figure 10, block [21]), thus commencing a new iteration cycle (Figure 10, block [6]). It is worth noting that eq 6 is not an explicit objective function; in other words, it does not express the design variable D in a real function.…”

“…Scaffolds are porous biomaterials imitating the properties of natural bone that provide a specific environment and architecture for bone growth and development . A number of research studies have been carried out that, based on different criteria, − aim at maximizing the scaffold performance, i.e., the attitude to promote and favor the tissue regeneration. It is commonly known that the scaffold ability to stimulate the formation of new bony tissue depends on a very large number of factors, among which, as demonstrated by recent in vitro and in vivo studies, − the scaffold design occupies a prominent place.…”