Review of additive manufactured tissue engineering scaffolds: relationship between geometry and performance

Material extrusion additive manufacturing has rapidly grown in use for tissue engineering research since its adoption in the year 2000. It has enabled researchers to produce scaffolds with intricate porous geometries that were not feasible with traditional manufacturing processes. Researchers can control the structural geometry through a wide range of customisable printing parameters and design choices including material, print path, temperature, and many other process parameters. Currently, the impact of these choices is not fully understood. This review focuses on how the position and orientation of extruded filaments, which sometimes referred to as the print path, lay-down pattern, or simply "scaffold design", affect scaffold properties and biological performance. By analysing trends across multiple studies, new understanding was developed on how filament position affects mechanical properties. Biological performance was also found to be affected by filament position, but a lack of consensus between studies indicates a need for further research and understanding. In most research studies, scaffold design was dictated by capabilities of additive manufacturing software rather than free-form design of structural geometry optimised for biological requirements. There is scope for much greater application of engineering innovation to additive manufacture novel geometries. To achieve this, better understanding of biological requirements is needed to enable the effective specification of ideal scaffold geometries

Combined 3D printing and part assembly manufacturing

Despite its irrefutable potential to change the way goods are produced, 3D printing technologies are, nowadays, employed to an insignificant amount of manufacturing processes in the production chain. While additive manufacturing, as the technology is also known, can be used for building objects of any shapes in a wide range of materials, the resulting products usually require costly post-processing steps for the incorporation of nonprintable parts that provide the object with useful functionalities. Such technologies could play a more important role in the manufacturing sector if they were enhanced so that these post-processing steps would be addressed during the building process and the resulting object would already be equipped with its final set of features. Aiming to add more functionalities to the parts produced by 3D printing techniques, this study introduces improvements to be applied to additive manufacturing machines. The technology introduced and demonstrated in this research, named Combined 3D Printing and Part Assembly (CPPA), merges the versatility of 3D printing with techniques to assemble external parts to the printed object in building time, allowing the manufacturing of products with functionalities beyond the ones provided by classic additive methods. While traditional 3D printing technologies can only create objects in a limited variety of materials, CPPA machines are capable of merging any sort of external parts to 3D printed structures.Apesar de seu irrefutável potencial de mudar o modo como bens são produzidos, a tecnologia de impressão 3D são empregadas em uma insignificante parcela dos processos de manufatura na cadeia produtiva. Ao mesmo tempo que a manufatura aditiva, como a tecnologia também é conhecida, é capaz de gerar objetos de qualquer formato em uma imensa gama de materiais, os produtos resultantes frequentemente necessitam de etapas de pós-processamento altamente custosas para a incorporação de partes não imprimíveis que proporcionam funcionalidades úteis ao objeto. Tais tecnologias poderiam exercer um papel mais importante no setor de manufatura se passassem por melhorias que permitissem que essas etapas de pós-processamento fossem executadas durante o próprio processo de impressão, de forma que o o objeto resultante já estivesse equipado com o seu conjunto de funcionalidades final. Visando adicionar mais funcionalidades aos objetos produzidos com técnicas de impressão 3D, esse estudo apresenta aperfeiçoamentos a serem aplicados em equipamentos de manufatura aditiva. A tecnologia denominada Combined 3D Printing and Part Assembly (CPPA) introduzida e demonstrada nessa pesquisa tem por objetivo combinar a versatilidade da impressão 3D com a anexação de peças externas ao objeto em tempo de impressão, de modo a criar produtos com funcionalidades além das fornecidas por métodos aditivos clássicos. Enquanto tecnologias tradicionais de impressão 3D criam objetos com uma variedade muito limitada de materiais, máquinas CPPA são capazes de incorporar peças externas de qualquer tipo a estruturas impressas em 3D

3D printed-poly(lactic acid) scaffolds with improved bioactivity for bone tissue engineering

PLA scaffolds produced by 3D printing are a promising alternative to bone tissue engineering. A simple mussel inspired method, polydopamine (PDA) surface functionalization, has being proposed as an efficient way to enhance the bioactivity of biomaterials, such as PLA, and to promote covalent immobilization of a variety of proteins such as collagen (COL) type I. This study aimed to characterize PLA scaffolds produced by FDM with different pore size, concomitantly to the influence of PDA coating as platform to enhance the bioactivity and the immobilization of COL I onto printed PLA. Scaffolds geometry influenced directly in the porosity and compressive strength of printed parts. The PDA layer improved the COL immobilization onto the surface of PLA scaffolds in 92% and enhanced the adhesion of porcine Bone Marrow Stem Cells (MSCs). The combination of PDA and COL layers provided the best conditions for early stage cell adhesion and proliferation. Cells cultured onto PDA/COL scaffolds produced substantially higher amounts of Alkaline Phosphatase (ALP), a marker of osteogenesis, by 21 days in culture. Scaffolds with projected pores of 700 µm in size (strut spacing = 1 mm) and coated with PDA plus COL I provides appropriate porosity, mechanical properties and biological conditions to allow bone tissue regeneration.Arcabouços de poli(ácido láctico) (PLA) produzidos por impressão 3D são uma alternativa promissora na engenharia tecidual. A funcionalização da superfície baseada no modelo de mexilhão – Polidopamina (PDA), foi proposta como uma maneira eficiente de aumentar a bioatividade e promover a imobilização covalente de biomoléculas, tais como o colágeno (COL) tipo I, nas superfícies. Este estudo teve como objetivo caracterizar arcabouços de PLA produzidos por impressão 3D, com diferentes espaçamentos entre os filamentos, concomitantemente à influência do recobrimento com PDA como plataforma para aumentar a bioatividade e a imobilização de COL I na superfície dos arcabouços. A geometria influenciou diretamente na porosidade e na resistência à compressão das peças impressas. A camada de PDA melhorou a imobilização de COL I na superfície dos arcabouços em 92% e aumentou a adesão de células-tronco mesenquimais. A sobreposição de PDA e COL I forneceu as melhores condições para adesão celular e proliferação no estágio inicial da cultura celular. Além disso, nessa condição, células produziram quantidade expressivamente maior de fosfatase alcalina, um conhecido marcador de osteogênese, após 21 dias em cultura. Os arcabouços com poros projetados de 700 µm (espaçamento intermediário = 1 mm) e revestidos com PDA/COL proporcionam porosidade, tamanho de poro, propriedades mecânicas e condições biológicas adequadas para permitir a regeneração do tecido ósseo

The Evolution of 3D Printing in AEC: From Experimental to Consolidated Techniques

The chapter leads the reader through the historical development of additive manufacturing (AM) techniques until the most recent developments. A tentative taxonomy is added to the historical perspective, in order to better understand the main lines of development and the potential cross-fertilization opportunities. Some case studies are analyzed in order to provide a clearer picture of the practical applications of AM in architecture engineering and construction (AEC), with a particular attention to the use of AM for final products rather than just prototypes. Eventually, some thoughts are shared as to the impact of AM on AEC beyond the mere cost-effectiveness and well into the potential change of paradigms in how architecture can be thought of and further developed embracing the new world of opportunities brought by AM

Working Performatively with Interactive 3D Printing: An artistic practice utilising interactive programming for computational manufacturing and livecoding

This thesis explores the liminal space where personal computational art and design practices and mass-manufacturing technologies intersect. It focuses on what it could look and feel like to be a computationally-augmented, creative practitioner working with 3D printing in a more programmatic, interactive way. The major research contribution is the introduction of a future-looking practice of Interactive 3D Printing (I3DP).I3DP is articulated using the Cognitive Dimensions of Notations in terms of associated user activities and design trade-offs. Another contribution is the design, development, and analysis of a working I3DP system called LivePrinter. LivePrinter is evaluated through a series of qualitiative user studies and a personal computational art practice, including livecoding performances and 3D form-making

Systemic circular economy solutions for fiber reinforced composites

This open access book provides an overview of the work undertaken within the FiberEUse project, which developed solutions enhancing the profitability of composite recycling and reuse in value-added products, with a cross-sectorial approach. Glass and carbon fiber reinforced polymers, or composites, are increasingly used as structural materials in many manufacturing sectors like transport, constructions and energy due to their better lightweight and corrosion resistance compared to metals. However, composite recycling is still a challenge since no significant added value in the recycling and reprocessing of composites is demonstrated. FiberEUse developed innovative solutions and business models towards sustainable Circular Economy solutions for post-use composite-made products. Three strategies are presented, namely mechanical recycling of short fibers, thermal recycling of long fibers and modular car parts design for sustainable disassembly and remanufacturing. The validation of the FiberEUse approach within eight industrial demonstrators shows the potentials towards new Circular Economy value-chains for composite materials

Systemic Circular Economy Solutions for Fiber Reinforced Composites

This open access book provides an overview of the work undertaken within the FiberEUse project, which developed solutions enhancing the profitability of composite recycling and reuse in value-added products, with a cross-sectorial approach. Glass and carbon fiber reinforced polymers, or composites, are increasingly used as structural materials in many manufacturing sectors like transport, constructions and energy due to their better lightweight and corrosion resistance compared to metals. However, composite recycling is still a challenge since no significant added value in the recycling and reprocessing of composites is demonstrated. FiberEUse developed innovative solutions and business models towards sustainable Circular Economy solutions for post-use composite-made products. Three strategies are presented, namely mechanical recycling of short fibers, thermal recycling of long fibers and modular car parts design for sustainable disassembly and remanufacturing. The validation of the FiberEUse approach within eight industrial demonstrators shows the potentials towards new Circular Economy value-chains for composite materials

Plataforma de modelação e controlo para impressoras 3D

Mestrado em Engenharia de Computadores e Telemática3D printers are becoming cheaper and widely used in various market segments as architecture, industrial design, automotive and aerospace engineering, providing an easy and cheaper way to produce parts and mockups. Although applications for controlling 3D printers exist, they are still poor in graphical design and difficult to use or understand due the advanced knowledge required. Most 3D printing applications allow importing and rendering a model with a 3D engine, and printing it with advanced configurations. Taking this into consideration it is intended to design and evaluate an application that presents common and advanced funcionalities through a simple, stable and easy to use user interface. An application (BEESOFT) was designed and developed taking the above objectives into consideration. It enhances the way users interact with the BEETHEFIRST printer, by providing an integrated environment where each user can, in a coordinated way, use the functionalities to quickly print. The simple user interface, the guided and self-explanatory wizards to help configure quickly the 3D printer and the robustness, error control and stability of the user interface, 3D engine and the communication protocol, distinguishes it from the other applications. This new application was evaluated using an usability testing plan and a heuristic evaluation analysis. Results confirm BEESOFT is an easy to use application that allows users with differents degrees of expertise to easily print a 3D model, but they also revealed some usability problems in the 3D canvas when modeling. The positive reaction and the results show BEESOFT simple, user spoken language and functional user interface with optimized printing profiles can be used in any sector of industry, education, etc.As impressoras 3D estão cada vez mais baratas sendo usadas em variados nichos de mercado como na arquitectura, design industrial, engenharia automóvel e aeroespacial, fornecendo uma forma fácil e barata de produzir partes e maquetes. Embora já existam aplicações de controlo de impressoras 3D, apresentam uma interface pobre e são difíceis de usar ou perceber devido ao conhecimento necessário. A maior parte das impressoras 3D permitem importar e processar um modelo 3D e imprimir com recurso a configurações avançadas. Tendo isto em consideração pretende-se desenvolver e avaliar uma aplicação constituida por funcionalidades básicas e avançadas com uma interface de utilizador estável e simples de usar. A aplicação (BEESOFT) foi projectada e desenvolvida tendo em consideração os objectivos acima referidos. E potencia o modo como os utilizadores interagem com a impressora BEETHEFIRST, fornecendo um ambiente integrado onde cada utilizador pode, de forma orientada, usar as funcionalidades para rapidamente imprimir. A interface de utilizador simples de usar, os assistentes e auto-explicativos para ajudar a configurar rapidamente a impressora 3D, a robustez, o controlo de erros, a estabilidade da interface de utilizador, o motor 3D e o protocolo de comunicação, destacam esta aplicação de outras existentes. Esta nova aplicação foi avaliada através de um plano de testes de usabilidade e de uma análise de avaliação heurística. Os resultados confirmam que o BEESOFT é uma aplicaçao fácil de usar e que permite aos utilizadores, com variados níveis de experiência, imprimir facilmente um modelo 3D, mas também reveleram alguns problemas de usabilidade no motor 3D aquando de operações de modelação. A reacção positiva e os resultados mostraram que a interface de utilizador do BEESOFT é simples, funcional, com uma linguagem acessível e com perfis de impressão optimizados, possibilitando o seu uso em qualquer sector da indústria, educação, etc

Systemic Circular Economy Solutions for Fiber Reinforced Composites

This open access book provides an overview of the work undertaken within the FiberEUse project, which developed solutions enhancing the profitability of composite recycling and reuse in value-added products, with a cross-sectorial approach. Glass and carbon fiber reinforced polymers, or composites, are increasingly used as structural materials in many manufacturing sectors like transport, constructions and energy due to their better lightweight and corrosion resistance compared to metals. However, composite recycling is still a challenge since no significant added value in the recycling and reprocessing of composites is demonstrated. FiberEUse developed innovative solutions and business models towards sustainable Circular Economy solutions for post-use composite-made products. Three strategies are presented, namely mechanical recycling of short fibers, thermal recycling of long fibers and modular car parts design for sustainable disassembly and remanufacturing. The validation of the FiberEUse approach within eight industrial demonstrators shows the potentials towards new Circular Economy value-chains for composite materials