Multi - Parameter Optimization for Two-Phase Unit-Cell based Tissue Scaffolds (original) (raw)
Related papers
Engineered tissue scaffolds with variational porous architecture
Journal of biomechanical engineering, 2011
This paper presents a novel computer-aided modeling of 3D tissue scaffolds with a controlled internal architecture. The complex internal architecture of scaffolds is biomimetically modeled with controlled micro-architecture to satisfy different and sometimes conflicting functional requirements. A functionally gradient porosity function is used to vary the porosity of the designed scaffolds spatially to mimic the functionality of tissues or organs. The three-dimensional porous structures of the scaffold are geometrically partition into functionally uniform porosity regions with a novel offsetting operation technique described in this paper. After determining the functionally uniform porous regions, an optimized deposition-path planning is presented to generate the variational internal porosity architecture with enhanced control of interconnected channel networks and continuous filament deposition. The presented methods are implemented, and illustrative examples are presented in this paper. Moreover, a sample optimized tool path for each example is fabricated layer-by-layer using a micronozzle biomaterial deposition system.
Functionally heterogeneous porous scaffold design for tissue engineering
2013
Most of the current tissue scaffolds are mainly designed with homogeneous porosity which does not represent the spatial heterogeneity found in actual tissues. Therefore engineering a realistic tissue scaffolds with properly graded properties to facilitate the mimicry of the complex elegance of native tissues are critical for the successful tissue regeneration. In this work, novel bio-mimetic heterogeneous porous scaffolds have been modeled. First, the geometry of the scaffold is extracted along with its internal regional heterogeneity. Then the model has been discretized with planner slices suitable for layer based fabrication. An optimum filament deposition angle has been determined for each slice based on the contour geometry and the internal heterogeneity. The internal region has been discritized considering the homogeneity factor along the deposition direction. Finally, an area weight based approach has been used to generate the spatial porosity function that determines the filament deposition location for desired biomimetic porosity. The proposed methodology has been implemented and illustrative examples are provided. The effective porosity has been compared between the proposed design and the conventional homogeneous scaffolds. The result shows a significant error reduction towards achieving the biomimetic porosity in the scaffold design and provides better control over the desired porosity level. Moreover, sample designed structures have also been fabricated with a NC motion controlled micro-nozzle biomaterial deposition system.
Prediction of Patient-Specific Tissue Engineering Scaffolds for Optimal Design
The fabrication of patient-specific tissue engineering scaffold is highly appreciated that requires prior estimation of porous and mechanical characteristics. Architectural controllability and reproducibility are also essential aspects in the development of 3D functional scaffolds. This work presents a computational approach to determine porous and mechanical characteristics of 3D scaffolds. The computational modeling could be a powerful tool to assist designing 3D scaffold with optimum characteristics as required for a particular patient in need. The 3D scaffolds were successfully modeled investigating the influences of design parameters on the porous and mechanical properties via finite element analysis (FEA) and ANSYS application software. It was revealed by ANSYS that the increase in porosity decreased the mechanical properties and increased the damping factor. The Scaffold porosities were obtained in the range of 47% to 95% with varying pore shape and size by modulating lay-down pattern, filament diameter and filament distance.
In developing 3D tissue engineering (TE) scaffolds via rapid prototyping system, the design parameters such as filament gap, filament diameter and lay down angle which play significant roles in controlling porous and mechanical characteristics can be modulated. This study focuses on developing a computational model to simulate porous and mechanical characteristics of 3D tissue engineering scaffolds. The simulation is performed by manipulating the design inputs and analyzing the influences of change of the parameters on porous and mechanical characteristics of the scaffolds. With a constant filament gap, the increase of filament diameter decreases porosity and thus increases the mechanical properties of the scaffolds. However, with a constant filament diameter, the increase of filament gap increases the porosity and consequently, decreases the scaffolds' mechanical properties. Increasing lay down angle also increases the porosity that also influences the mechanical properties of the scaffolds. The actual mechanical properties of scaffolds are always obtained through physical experiments.
Designing heterogeneous porous tissue scaffolds for additive manufacturing processes
Computer-Aided Design, 2013
h i g h l i g h t s • Heterogeneous porous architecture of tissue scaffolds is designed. • To improve cell survivability, radial channels are optimally generated. • Iso-porous curves are optimally determined to generate the spatial porosity. • A continuous deposition path planning is developed for additive processes.
A Computational Algorithm for Optimal Design of Bioartificial Organ Scaffold Architectures
bioRxiv (Cold Spring Harbor Laboratory), 2024
We develop a computational algorithm based on a diffuse interface approach to study the design of bioartificial organ scaffold architectures. These scaffolds, composed of poroelastic hydrogels housing transplanted cells, are linked to the patient's blood circulation via an anastomosis graft. Before entering the scaffold, the blood flow passes through a filter, and the resulting filtered blood plasma transports oxygen and nutrients to sustain the viability of transplanted cells over the long term. A key issue in maintaining cell viability is the design of ultrafiltrate channels within the hydrogel scaffold to facilitate advection-enhanced oxygen supply ensuring oxygen levels remain above a critical threshold to prevent hypoxia. In this manuscript, we develop a computational algorithm to analyze the plasma flow and oxygen concentration within hydrogels featuring various channel geometries. Our objective is to identify the optimal hydrogel channel architecture that sustains oxygen concentration throughout the scaffold above the critical hypoxic threshold. The computational algorithm we introduce here employs a diffuse interface approach to solve a multi-physics problem. The corresponding model couples the time-dependent Stokes equations, governing blood plasma flow through the channel network, with the time-dependent Biot equations, characterizing Darcy velocity, pressure, and displacement within the poroelastic hydrogel containing the transplanted cells. Subsequently, the calculated plasma velocity is utilized to determine oxygen concentration within the scaffold using a diffuse interface advection-reaction-diffusion model. Our investigation yields a scaffold architecture featuring a hexagonal channel network geometry that meets the desired oxygen concentration criteria. Unlike classical sharp interface approaches, the diffuse interface approach we employ is particularly adept at addressing problems with intricate interface geometries, such as those encountered in bioartificial organ scaffold design. This study is significant because recent developments in hydrogel fabrication make it now possible to control hydrogel rheology [20, 14], and utilize computational results to generate optimized scaffold architectures.
Applied Mechanics and Materials
To produce multi-material scaffolds for Tissue Engineering accurate techniques are needed in order to obtain three-dimensional constructs with clinically appropriate size and structural integrity. This paper presents a novel biomanufacturing system that can fabricate 3D scaffolds with precise shape and porosity which is achieved through the control of all fabrication modules by an integrated computational platform. The incorporation of a clean flow unit and a camera allows to obtain scaffolds in a clean environment and provides a monitoring tool to analyse constructs during the production, respectively. In this research work is demonstrated that the new system enables the fabrication of multi-material 3D structures using poly (e-caprolactone) and sodium alginate for potential use in Tissue Engineering applications.
Spatially Multi-functional Porous Tissue Scaffold
Procedia Engineering, 2013
A novel tissue scaffold design technique has been proposed with controllable heterogeneous architecture design suitable for additive manufacturing processes. The proposed layer-based design uses a bi-layer pattern of radial and spiral layer consecutively to generate functionally gradient porosity, which follows the geometric shape of the scaffold. The proposed approach constructs the medial region from the medial axis of each corresponding layer. The radial layers of the scaffold are then generated by connecting the boundaries of the medial region and the layer's outer contour. Gradient porosity is changed between the medial region and the layer's outer contour. Iso-porosity regions are determined by dividing the sub-regions peripherally into pore cells and consecutive iso-porosity curves are generated using the iso-points from those pore cells. The combination of consecutive layers generates the pore cells with desired pore sizes. To ensure the fabrication of the designed scaffolds, the generated contours are optimized for a continuous, interconnected, and smooth deposition path-planning. The proposed methodologies can generate the structure with gradient (linear or non-linear), variational or constant porosity that can provide localized control of variational porosity along the scaffold architecture. The designed porous structures can be fabricated using additive Manufacturing processes.