Computational Design, Freeform Fabrication and Testing of Nylon-6 Tissue Engineering Scaffolds

2002 ◽  
Vol 758 ◽  
Author(s):  
Suman Das ◽  
Scott J. Hollister ◽  
Colleen Flanagan ◽  
Adebisi Adewunmi ◽  
Karlin Bark ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Solid Freeform Fabrication ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Computational Design ◽  
Nylon 6 ◽  
Functionally Graded ◽  
Tissue Engineering Scaffolds ◽  
Freeform Fabrication

ABSTRACTAdvanced and novel fabrication methods are needed to build complex three-dimensional scaffolds that incorporate multiple functionally graded biomaterials with a porous internal architecture that will enable the simultaneous growth of multiple tissues, tissue interfaces and blood vessels. The aim of this research is to develop, demonstrate and characterize techniques for fabricating such scaffolds by combining solid freeform fabrication and computational design methods. When fully developed, such techniques are expected to enable the fabrication of tissue engineering scaffolds endowed with functionally graded material composition and porosity exhibiting sharp or smooth gradients. As a first step towards realizing this goal, scaffolds with periodic cellular and biomimetic architectures were designed and fabricated using selective laser sintering in Nylon-6, a biocompatible polymer. Results of bio-compatibility and in vivo implantation studies conducted on these scaffolds are reported.

A Computational Design Framework for a Rapid Solid Freeform Fabrication Process

2000 ◽  
Author(s):  
Deepesh Khandelwal ◽  
T. Kesavadas
Keyword(s):  
Solid Freeform Fabrication ◽  
Optimization Technique ◽  
Three Dimensional ◽  
Computational Design ◽  
Freeform Fabrication ◽  
3D Cad ◽  
Build Time ◽  
Cad Models ◽  
Efficient Machine ◽  
Novel Concept

Abstract Solid Freeform Fabrication (SFF) techniques in recent years have shown tremendous promise in reducing the design time of products. This technique enables designers to get three-dimensional physical prototypes from 3D CAD models. Although SFF has gained popularity, the manufacturing time and cost have limited its use to small and medium sized parts. In this paper we have proposed a novel concept for rapidly building SFF parts by inserting prefabricated inserts into the fabricated part. A computational algorithm was developed for determining ideal placement of inserts/cores in the CAD model of the part being prototyped using a heuristic optimization technique called Simulated Annealing. This approach will also allow the designers to build multi-material prototypes using the Rapid Prototyping (RP) technique. By using cheaper pre-fabricates instead of costly photopolymers, the production cost of the SFFs can be reduced. Additionally it will also reduce build time, resulting in efficient machine utilization.

Direct Freeform Fabrication Technique for Bio-Manufacturing of Pre-Seeded, Spatially Heterogeneous, Anatomically-Shaped Alginate Hydrogel Implants

2005 ◽  
Author(s):  
Daniel L. Cohen ◽  
Evan Malone ◽  
Hod Lipson ◽  
Lawrence J. Bonassar
Keyword(s):  
Tissue Engineering ◽  
Solid Freeform Fabrication ◽  
Crosslinking Agent ◽  
Three Dimensional ◽  
Patient Specific ◽  
Efficient Production ◽  
Alginate Hydrogel ◽  
Freeform Fabrication ◽  
Patient Specific Implants ◽  
Multiple Material

A major challenge in orthopaedic tissue engineering is the generation of cell-seeded implants with structures that mimic native tissue, both in terms of anatomic geometries and intratissue cell distributions. By combining the strengths of injection molding tissue engineering with those of Solid Freeform Fabrication (SFF), three-dimensional pre-seeded implants were fabricated without custom-tooling, enabling efficient production of patient-specific implants. The incorporation of SFF technology also enables the fabrication of geometrically complex, multiple-material implants with spatially heterogeneous cell distributions that could not otherwise be produced. Using a custom-built robotic SFF platform and gel deposition tools, alginate hydrogel was used with calcium sulfate as a crosslinking agent to produce pre-seeded living implants of arbitrary geometries. The process was determined to be sterile and viable at 94±5%. The GAG production was found to be about half that of a similarly molded samples. The compressive elastic modulus was determined to be 1.462±0.113 kPa.

Development of HA-PLGA Scaffold Encapsulating Intact BMP-2 Using Solid Freeform Fabrication Technology

2011 ◽  
Author(s):  
Jin-Hyung Shim ◽  
Jong Young Kim ◽  
Kyung Shin Kang ◽  
Jung Kyu Park ◽  
Sei Kwang Hahn ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Regeneration ◽  
Porous Scaffold ◽  
Solid Freeform Fabrication ◽  
Three Dimensional ◽  
Porous Scaffolds ◽  
Prolonged Release ◽  
Cellular Activity ◽  
Freeform Fabrication

Tissue engineering is an interdisciplinary field that focuses on restoring and repairing tissues or organs. Cells, scaffolds, and biomolecules are recognized as three main components of tissue engineering. Solid freeform fabrication (SFF) technology is required to fabricate three-dimensional (3D) porous scaffolds to provide a 3D environment for cellular activity. SFF technology is especially advantageous for achieving a fully interconnected, porous scaffold. Bone morphogenic protein-2 (BMP-2), an important biomolecule, is widely used in bone tissue engineering to enhance bone regeneration activity. However, methods for the direct incorporation of intact BMP-2 within 3D scaffolds are rare. In this work, 3D porous scaffolds with poly(lactic-co-glycolic acid) chemically grafted hyaluronic acid (HA-PLGA), in which intact BMP-2 was directly encapsulated, were successfully fabricated using SFF technology. BMP-2 was previously protected by poly(ethylene glycol) (PEG), and the BMP-2/PEG complex was incorporated in HA-PLGA using an organic solvent. The HAPLGA/PEG/BMP-2 mixture was dissolved in chloroform and deposited via a multi-head deposition system (MHDS), one type of SFF technology, to fabricate a scaffold for tissue engineering. An additional air blower system and suction were installed in the MHDS for the solvent-based fabrication method. An in vitro evaluation of BMP-2 release was conducted, and prolonged release of intact BMP-2, for up to 28 days, was confirmed. After confirmation of advanced proliferation of pre osteoblasts, a superior differentiation effect of the HA-PLGA/PEG/BMP-2 scaffold was validated by measuring high expression levels of bone-specific markers, such as alkaline phosphatase (ALP) and osteocalcin (OC). We show that our solvent-based fabrication is a non-toxic method for restoring cellular activity. Moreover, the HAPLGA/PEG/BMP-2 scaffold was effective for bone regeneration.

Bone Tissue Scaffold Technologies Based on RP Adopted Droplet Assembly

2002 ◽  
Vol 758 ◽  
Author(s):  
Renji Zhang ◽  
Yongnian Yan ◽  
Feng Lin
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue ◽  
Solid Freeform Fabrication ◽  
Deposition Process ◽  
Layer By Layer ◽  
Tissue Engineering Scaffolds ◽  
Molecular Scaffold ◽  
Tissue Scaffold ◽  
Freeform Fabrication ◽  
Assembly Technology

ABSTRACTTissue engineering tries to grow replacement tissues to repair damaged bones. In this paper, the fabrication technology of Multi-nozzle Deposition Manufacturing (MDM) was adopted to fabricate scaffolds of a tissue engineered bone at low temperature. The composite of poly(L-lactic acid) and tri-calcium phosphate (TCP) was chosen to form bone tissue engineering scaffolds. The new computer aided manufacturing process can make porous PLLA/TCP scaffolds. A new surface processing technology of apatite coating on bone tissue engineered scaffolds was also adopted. This digital forming technology was based on rapid prototyping (RP), in which a digital droplets assembly technology was introduced. The MDM technology of 4 nozzles was developed based on the layer-by-layer manufacturing principle of Solid Freeform Fabrication (SFF) in our laboratory. The bone scaffolds made by the multi-nozzle deposition process in the MDM system have good biocompatibility and bone conductive properties as a molecular scaffold for bone morphogenic protein (BMP) in the implantation experiment of repairing segment defects in rabbits' and dogs' radiuses.

Freeform fabrication of Nylon‐6 tissue engineering scaffolds

2003 ◽  
Vol 9 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Suman Das ◽  
Scott J. Hollister ◽  
Colleen Flanagan ◽  
Adebisi Adewunmi ◽  
Karlin Bark ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Nylon 6 ◽  
Tissue Engineering Scaffolds ◽  
Freeform Fabrication

Solid Freeform Fabrication of Ceramics Using Selective Laser Sintering and Selective Area Laser Deposition

1991 ◽  
Vol 249 ◽  
Author(s):  
Uday Lakshminarayan ◽  
Guisheng Zong ◽  
W. Richards Thissell ◽  
Harris L. Marcus
Keyword(s):  
Gas Phase ◽  
Solid Freeform Fabrication ◽  
Laser System ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Laser Deposition ◽  
Powder Materials ◽  
Freeform Fabrication ◽  
Selective Area

ABSTRACTSolid Freeform Fabrication (SFF) is a new computer fabrication technique that does not require any part specific tooling. The starting material can be either solid, liquid or gaseous. The part can be made from metallic, ceramic, polymeric or a composite material. The concept is to use a solid modeling system to define the part of interest and to reduce the model to a set of toggle point data that totally define the geometry. In Selective Laser Sintering the sectioned component is then combined with a rastered laser system that impinges on the precursor powder materials in a layered reconstruction of the three dimensional CAD designed part. The part is then formed in this manner. This approach to producing the part involves a great deal of understanding of the laser materials interactions, the appropriate choice of materials specific to this processing and how the total process integrates. Application to ceramic powders will be described. An alternative approach to SFF is Selective Area Laser Deposition where the three dimensional part is made from the gas phase. The initial gas deposition studies involving deposition of carbon from hydrocarbons will be discussed. For both of the above SFF approaches the laser beam powder and gas phase interactions and the microstructure of the resulting three dimensional forms as a function of system parameters will be described.

Strengthening Porous Skeletons by Metal Deposition from a Nanoparticle Suspension

2004 ◽  
Vol 860 ◽  
Author(s):  
Nathan B. Crane ◽  
Emanuel M. Sachs ◽  
Andreas Frank
Keyword(s):  
Solid Freeform Fabrication ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Nanoparticle Suspension ◽  
Three Dimensional Printing ◽  
Freeform Fabrication ◽  
Porous Bodies ◽  
Infiltration Temperature ◽  
Dimensional Printing ◽  
Infiltration Techniques

ABSTRACTSolid freeform fabrication (SFF) processes such as three-dimensional printing (3DP) and selective laser sintering (SLS) produce porous bodies that must be densified for many applications. New homogenous infiltration techniques can produce dense, homogenous parts of selected standard alloys, but the increased infiltration temperature dramatically increases creep deflection under self-weight. This paper reports on a method that improves dimensional stability by reducing creep deflection rates at high temperature. This method is applicable to all metal skeletons that must be strengthened without increasing shrinkage. In this method, the skeletons are reinforced by the addition of nanometer-sized particles dispersed in a liquid. The liquid is applied to the structure either during 3DP printing or after forming (3DP, SLS, pressing). The liquid is then evaporated, depositing the metal in the skeleton. The metal nanoparticles are sintered to density below the sintering temperature of the micron-scale skeleton particles. This concept is demonstrated using a suspension of 8–10 nm iron particles infiltrated into lightly sintered porous steel skeletons. When heated with an unsupported overhang to a typical infiltration temperature, creep deflection was reduced 50–80% with 0.5–1 wt% added metal.

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