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Projeto de investigação
Multimaterial microstereo-thermal-lithography (μSTLG)
Financiador
Autores
Publicações
Photocrosslinkable Materials for the Fabrication of Tissue-Engineered Constructs by Stereolithography
Publication . Pereira, Rúben F.; Bártolo, Paulo J.
Stereolithography is an additive technique that produces three-dimensional (3D) solid objects using a multi-layer procedure through the selective photoinitiated curing reaction of a liquid photosensitive material. Stereolithographic processes have been widely employed in Tissue Engineering for the fabrication of temporary constructs, using natural and synthetic polymers, and polymer-ceramic composites. These processes allow the fabrication of complex structures with a high accuracy and precision at physiological temperatures, incorporating cells and growth factors without significant damage or denaturation. Despite recent advances on the development of novel biomaterials and biocompatible crosslinking agents, the main limitation of these techniques are the lack number of available photocrosslinkable materials, exhibiting appropriate biocompatibility and biodegradability. This chapter gives an overview of the current state-of-art of materials and stereolithographic techniques to produce constructs for tissue regeneration, outlining challenges for future research.
Thermo-kinetic curing model for stereolithographic applications
Publication . Bártolo, Paulo
A thermal-kinetic model, using the finite element method to study, simulate and optimise stereolithography, is presented in this paper. The model, which is theoretically rigorous and practical in its implementation, describes both the heat transfer effects and the course of the chemical reaction. This model includes the effects of photo-initiator concentration, temperature and light intensity, predicting the diffusion-controlled effects that occur after vitrification, the phenomenon of unimolecular termination and the shrinkage effects. Light intensity values at the resin surface are defined by assuming an appropriated Gaussian intensity distribution. The Beer-Lambert law enables to describe the decrease in light intensity with depth. The non-linear variation of the glass transition temperature with fractional conversion can be determined and consequently the mechanical behaviour of the resin sample predicted.
Computational technologies in tissue engineering
Publication . Almeida, H. A.; Bártolo, P. J.
In last decades, many advances have been made in order to aid the medical community. Numerous computational technologies have been developed and improved the efficiency in diagnostic and treatment of many diseases. Many of the technologies were developed with the main goal of aiding in the research of genetic and viral diseases. Tissue engineering is a multidisciplinary field that requires the combined effort of cell biologists, engineers, material scientists, mathematicians, geneticists, and clinicians toward the development of biological substitutes that restore, maintain, or improve tissue function. The success of this emerging medical domain relies on the current technological advances. This paper presents an overview of the existing computational technologies that have been implemented in tissue engineering and the design of scaffolds for tissue engineering applications. These computational technologies contemplate medical imaging processing, numerical calculations (structural, vascular and topological) and biofabrication techniques necessary for the scaffolds optimum design and production.
Thermal Stability of PCL/PLA Blends Produced by Physical Blending Process
Publication . Patrício, Tatiana; Bártolo, Paulo
The poly ɛ-caprolactone (PCL) and poly lactid acid (PLA) were used for prepared blends with different percentage. PCL/PLA blends (70/30 wt% and 50/50 wt%) were prepared by physical blending process, called solvent casting. These blends were analysed by morphological, thermal and rheological tests in order to evaluate the miscibility and thermal stability of the polymers and their blends, important characteristics to apply in scaffold fabrication. The Simultaneous Thermal Analyser (STA) demonstrated two separated melting peaks in the blends, which show the immiscible polymers. The blends surface were analysed through Scanning Electron Microscope (SEM) and the results shows the presence of droplets in the blends surface, characteristic of an immiscible polymer. The results of rheological measurements present a good thermal stability of the polymers and their blends.
Design of tissue engineering scaffolds based on hyperbolic surfaces: Structural numerical evaluation
Publication . Almeida, Henrique A.; Bártolo, Paulo J.
Tissue engineering represents a new field aiming at developing biological substitutes to restore, maintain, or improve tissue functions. In this approach, scaffolds provide a temporary mechanical and vascular support for tissue regeneration while tissue in-growth is being formed. These scaffolds must be biocompatible, biodegradable, with appropriate porosity, pore structure and distribution, and optimal vascularization with both surface and structural compatibility. The challenge is to establish a proper balance between porosity and mechanical performance of scaffolds.This work investigates the use of two different types of triple periodic minimal surfaces, Schwarz and Schoen, in order to design better biomimetic scaffolds with high surface-to-volume ratio, high porosity and good mechanical properties. The mechanical behaviour of these structures is assessed through the finite element method software Abaqus. The effect of two parametric parameters (thickness and surface radius) is also evaluated regarding its porosity and mechanical behaviour.
Unidades organizacionais
Descrição
Palavras-chave
Stereolitography,Micro-manufacturing,Photopolymerisation,Rapid prototyping, Engineering and technology ,Engineering and technology/Materials engineering
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia, I.P.
Fundação para a Ciência e a Tecnologia, I.P.
Fundação para a Ciência e a Tecnologia, I.P.
Programa de financiamento
5876-PPCDTI
Concurso para Projectos de I&D em todos os Domínios Científicos - 2008
Concurso para Projectos de I&D em todos os Domínios Científicos - 2008
Número da atribuição
PTDC/EME-PME/098037/2008