Tissue Engineered Bone Using Polycaprolactone Scaffolds Made by Selective Laser Sintering

2004 ◽  
Vol 845 ◽  
Author(s):  
J. M. Williams ◽  
A. Adewunmi ◽  
R. M. Schek ◽  
C. L. Flanagan ◽  
P. H. Krebsbach ◽  
...  

ABSTRACTPolycaprolactone is a bioresorbable polymer that has potential for tissue engineering of bone and cartilage. In this work, we report on the computational design and freeform fabrication of porous polycaprolactone scaffolds using selective laser sintering, a rapid prototyping technique. The microstructure and mechanical properties of the fabricated scaffolds were assessed and compared to designed porous architectures and computationally predicted properties. Compressive modulus and yield strength were within the lower range of reported properties for human trabecular bone. Finite element analysis showed that mechanical properties of scaffold designs and of fabricated scaffolds can be computationally predicted. Scaffolds were seeded with BMP-7 transduced fibroblasts and implanted subcutaneously in immunocompromised mice. Histological evaluation and micro-computed tomography (μCT) analysis confirmed that bone was generated in vivo. Finally, we have demonstrated the clinical application of this technology by producing a prototype mandibular condyle scaffold based on an actual pig condyle.

Author(s):  
Jie Niu ◽  
Hui Leng Choo ◽  
Wei Sun

The availability of additive manufacturing technologies in particular the selective laser sintering process has enabled the fabrication of high strength, lightweight and complex cellular lattice structures. In this study, the effective mechanical properties of selective laser sintering produced periodic lattice structures were investigated. Three different types of lattice structures were designed by repeating three types of open-form unit cells consisting of triangular prism, square prism and hexagonal prism. A novel approach of creating the complex and conformable lattice structures using traditional modelling software such as Creo® proposed by the authors was used. Based on the predesigned lattice structures, finite element analysis was carried out to evaluate the mechanical properties of these structures. For the experimental study, nylon samples were printed using a plastic selective laser sintering system and tested using a universal testing machine. Finite element analysis results show that lattice structures with triangular prism perform better than the other two prisms in terms of Young’s modulus to relative density ratio. Tensile tests results show good conformance with the results obtained from finite element analysis.


Author(s):  
Shenghui Lan ◽  
Abhishek Chandra ◽  
Ling Qin ◽  
X. Sherry Liu

Micro computed tomography (μCT) has been widely used to study 3-dimensional (3D) microstructure of bone specimens. In the recent decade, in vivo μCT scanners have become available to monitor longitudinal bone changes in rodents (1,2). The current in vivo μCT scan can obtain images with an isotropic voxel size up to 10.5 μm, which is high enough for direct 3D bone microstructural analyses. Moreover, based on these high-resolution images, micro finite element (μFE) models can be generated to estimate mechanical properties of bone. Therefore, by using in vivo μCT imaging and μFE analysis techniques, changes in geometry, microstructure, and mechanical properties of rodent bone, in response to either diseases or treatments, can be visualized and quantified over time.


2019 ◽  
Vol 9 (7) ◽  
pp. 1308 ◽  
Author(s):  
Rob Kleijnen ◽  
Manfred Schmid ◽  
Konrad Wegener

This work describes the production of a spherical polybutylene terephthalate (PBT) powder and its processing with selective laser sintering (SLS). The powder was produced via melt emulsification, a continuous extrusion-based process. PBT was melt blended with polyethylene glycol (PEG), creating an emulsion of spherical PBT droplets in a PEG matrix. Powder could be extracted after dissolving the PEG matrix phase in water. The extrusion settings were adjusted to optimize the size and yield of PBT particles. After classification, 79 vol. % of particles fell within a range of 10–100 µm. Owing to its spherical shape, the powder exhibited excellent flowability and packing properties. After powder production, the width of the thermal processing (sintering) window was reduced by 7.6 °C. Processing of the powder on a laser sintering machine was only possible with difficulties. The parts exhibited mechanical properties inferior to injection-molded specimens. The main reason lied in the PBT being prone to thermal degradation and hydrolysis during the powder production process. Melt emulsification in general is a process well suited to produce a large variety of SLS powders with exceptional flowability.


2019 ◽  
Vol 290 ◽  
pp. 08010
Author(s):  
Karolina Karolewska ◽  
Bogdan Ligaj

The most commonly used technology among the additive manufacturing is Direct Metal Laser Sintering (DMLS). This process is based on selective laser sintering (SLS). The method gained its popularity due to the possibility of producing metal parts of any geometry, which would be difficult or impossible to obtain by the use of conventional manufacturing techniques. Materials used in the elements manufacturing process are: titanium alloys (e.g. Ti6Al4V), aluminium alloy AlSi10Mg, etc. Elements printed from Ti6Al4V titanium alloy find their application in many industries. Details produced by additive technology are often used in medicine as skeletal, and dental implants. Another example of the DMLS elements use is the aerospace industry. In this area, the additive manufacturing technology produces, i.a. parts of turbines. In addition to the aerospace and medical industries, DMLS technology is also used in motorsport for exhaust pipes or the gearbox parts. The research objects are samples for static tests. These samples were made of Ti6Al4V alloy by the DMLS method and the rolling method from a drawn rod. The aim of the paper is the mechanical properties comparative analysis of the Ti6Al4V alloy produced by the DMLS method under static loading conditions and microstructure analysis of this material.


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