Modeling inspiration for innovative NPD: lessons from biomimetics

International audienceIn biomimetic design, nature - natural phenomena, systems or organisms - is used as a source of inspiration for producing new ideas or concepts. While being widely recommended this approach lacks rigorous analysis and manageable systematization that would be needed in industrial contexts. Better modeling of this process of bioinspiration is a condition for applying bioinspiration to stimulate innovation in a controlled way. This paper presents a model for bioinspiration based on the framework of the C-K design theory. This model was elaborated considering a review of the existing literature on methods for implementing biomimetic design and an analysis of selected biomimetic product development case examples. The results reveal the main roles of biological knowledge in the design process (1) indication of a "design direction", meaning an expansion on the concepts space, (2) indication of knowledge domains where no or few knowledge is available, (3) reorganization of the knowledge base, activating knowledge bases that would not otherwise be activated. This improved understanding of the bioinspiration process outlines more sophisticated and profound conditions that have to be managed for creating value

Revestimentos multicamada de diamante CVD micro/nanocristalino para biotribologia

Doutoramento em Ciência e Engenharia de MateriaisIn the present work multilayered micro/nanocrystalline (MCD/NCD) diamond coatings were developed by Hot Filament Chemical Vapour Deposition (HFCVD). The aim was to minimize the surface roughness with a top NCD layer, to maximize adhesion onto the Si3N4 ceramic substrates with a starting MCD coating and to improve the mechanical resistance by the presence of MCD/NCD interfaces in these composite coatings. This set of features assures high wear resistance and low friction coefficients which, combined to diamond biocompatibility, set this material as ideal for biotribological applications. The deposition parameters of MCD were optimized using the Taguchi method, and two varieties of NCD were used: NCD-1, grown in a methane rich gas phase, and NCD-2 where a third gas, Argon, was added to the gas mixture. The best combination of surface pre-treatments in the Si3N4 substrates is obtained by polishing the substrates with a 15 μm diamond slurry, further dry etching with CF4 plasma for 10 minutes and final ultrasonic seeding in a diamond powder suspension in ethanol for 1 hour. The interfaces of the multilayered CVD diamond films were characterized with high detail using HRTEM, STEM-EDX and EELS. The results show that at the transition from MCD to NCD a thin precursor graphitic film is formed. On the contrary, the transition of the NCD to MCD grade is free of carbon structures other than diamond, as a result of the richer atomic hydrogen content and of the higher substrate temperature for MCD deposition. At those transitions, WC nanoparticles were found due to contamination from the filament, being also present at the first interface of the MCD layer with the silicon nitride substrate. In order to study the adhesion and mechanical resistance of the diamond coatings, indentation and particle jet blasting tests were conducted, as well as tribological experiments with homologous pairs. Indentation tests proved the superior behaviour of the multilayered coatings that attained a load of 800 N without delamination, when compared to the mono and bilayered ones. The multilayered diamond coatings also reveal the best solid particle erosion resistance, due to the MCD/NCD interfaces that act as crack deflectors. These results were confirmed by an analytical model on the stress field distribution based on the von Mises criterion. Regarding the tribological testing under dry sliding, multilayered coatings also exhibit the highest critical load values (200N for Multilayers with NCD-2). Low friction coefficient values in the range μ=0.02- 0.09 and wear coefficient values in the order of ~10-7 mm3 N-1 m-1 were obtained for the ball and flat specimens indicating a mild wear regime. Under lubrication with physiological fluids (HBSS e FBS), lower wear coefficient values ~10-9-10-8 mm3 N-1 m-1) were achieved, governed by the initial surface roughness and the effective contact pressure.No presente trabalho desenvolveram-se revestimentos de diamante micro/nanocristalino (MCD/NCD) em multicamadas obtidos por deposição química em fase vapor (CVD) assistida por filamento quente. Pretendeu-se minimizar a rugosidade através de um camada superficial de NCD, maximizar a adesão com um filme inicial de MCD sobre substratos cerâmicos de nitreto de silício (Si3N4) e incrementar a resistência mecânica pela presença de interfaces MCD/NCD nestes revestimentos compósitos. Este conjunto de características garante elevada resistência ao desgaste e baixo coeficiente de atrito, o que somado à biocompatibilidade do diamante, configuram este material como ideal para aplicações em biotribologia. Os parâmetros de deposição do MCD foram otimizados usando o método de Taguchi e utilizaram-se duas variedades de NCD: NCD-1 crescido numa atmosfera com sobressaturação de metano e NCD-2 crescido na presença de árgon. A melhor combinação de pré-tratamentos nos substratos de Si3N4 consiste num polimento com suspensão de diamante (15 μm), seguido de ataque por plasma de CF4 durante 10 minutos e riscagem em suspensão de pó de diamante em etanol durante 1 hora. As interfaces das multicamadas de diamante foram caracterizadas em detalhe por HRTEM, STEM-EDX e EELS. Os resultados mostram que na transição de diamante MCD para NCD ocorre a formação de um filme fino de carbono amorfo, inexistente na transição de NCD para MCD, como resultado da maior percentagem de hidrogénio atómico na mistura de gases e do incremento da temperatura do substrato para a deposição de MCD. Uma característica comum nas interfaces nos dois tipos de NCD é a presença de partículas esféricas de carboneto de tungsténio, devido à contaminação pelos filamentos, estando também presentes na interface entre a camada de MCD e o substrato de nitreto de silício. A adesão e resistência mecânica dos filmes de diamante foram avaliadas por ensaios de indentação, erosão com partículas de carboneto de silício e ensaios tribológicos em movimento recíproco, com pares próprios. Por indentação verificou-se que as multicamadas suportam uma carga de 800N, sem delaminação, valor superior ao atingido pelas mono- e bicamadas. Nos ensaios de erosão, as multicamadas apresentaram igualmente melhor comportamento, devido à ação das interfaces MCD/NCD como defletoras das fissuras, sendo estes resultados confirmados por uma análise de distribuição de tensões de von Mises. As multicamadas apresentam também as cargas críticas de delaminação máximas nos ensaios tribológicos a seco (200 N para multicamadas com NCD-2). Os valores do coeficiente de atrito variam na gama μ=0.02-0.09, para coeficientes de desgaste ~10-7 mm3 N-1 m-1 para a esfera e placa, indicando um regime de desgaste moderado. Sob lubrificação de líquidos fisiológicos (HBSS e FBS) descem para ~10-9-10-8 mm3 N-1 m-1, valores determinados pela rugosidade de partida e pelo regime de pressão de contato efetiva

Ferramentas odontológicas de Si3N4 revestidas com diamante CVD

Mestrado em Engenharia de MateriaisOs filmes de diamante depositados por deposição Química em Fase Vapor (CVD) apresentam um grande potencial para aplicação como brocas para odontologia. No presente trabalho, brocas de cerâmicos à base de nitreto de silício, Si3N4, foram produzidas a partir de pós comerciais, sinterizadas sem pressão aplicada e maquinadas até à forma final, usando como modelo uma broca comercial de aço. O nitreto de silício usado como substrato garante elevados níveis de adesão para os filmes de diamante microcristalino e nanocristalino. Antes de efectuar a deposição dos filmes de diamante, as brocas sofreram um tratamento superficial por plasma de CF4 para aumentar a adesão dos filmes ao substrato, seguindo-se uma riscagem em suspensão de pó de diamante visando favorecer a nucleação do diamante durante a deposição. Filmes de diamante foram depositados pela técnica de CVD assistida por Filamento Quente (HFCVD) sobre brocas de Si3N4, começando por uma camada de diamante microcristalino que apresenta excelente adesão nestes cerâmicos, seguindo-se uma camada de diamante nanocristalino de baixa rugosidade. Os filmes foram caracterizados microestruturalmente por SEM e espectroscopia Raman. Por SEM foi possível observar a densidade e homogeneidade dos filmes depositados e por espectroscopia Raman verificouse a qualidade dos filmes depositados. Antes da colocação de um implante dentário no leito mandibular é necessário proceder à furação do osso com brocas de dimensão adequada. Para efectuar os ensaios de furação foi utilizada uma máquina de ensaios mecânicos universal, com um berbequim de velocidade variável acoplado. Para simular o osso mandibular humano foi utilizado um bloco de espuma rígida de poliuretano (ASTM F-1839). A velocidade de corte e o aumento local de temperatura durante o corte são parâmetros essenciais para o sucesso do implante. Nos ensaios de furação efectuados a velocidade de corte variou na gama 50-1400 RPM, oscilando a velocidade de penetração entre 7,5 e 30 mm/min. O aumento de temperatura foi monitorizado durante o corte através de dois termopares acoplados ao polímero, a alturas de penetração diferentes. Pelos resultados obtidos foi possível concluir que as brocas de Si3N4 revestidas por HFCVD com a bicamada MCD/NCD apresentam melhor desempenho, tanto a alta como a baixa velocidade de corte, quando comparadas com as brocas comerciais de aço (AISI 420) usadas como referência: força de avanço cerca de 4 vezes menor; aumento da temperatura local inferior em cerca de 4ºC; possibilidade de corte a velocidades de rotação reduzidas (100 RPM), o que permite a recolha de aparas de osso autógeno; possibilidade de corte com elevada velocidade de penetração (30 mm/min), o que reduz significativamente a duração do procedimento. ABSTRACT: Diamond films deposited by Chemical Vapour Deposition (CVD) have a good potential for applications such as odontological drill bits. In the present work, Si3N4 based ceramic drill bits were produced starting from commercial powders, sintered without applied pressure and machined until final shape, using a commercial steel drill bit as reference. The silicon nitride used as substrate provides high adhesion levels for micro and nanocrystalline (NCD) diamond films. Before film deposition the ceramics are submitted to a CF4 plasma treatment (plasma etching) to enhance the film adhesion onto the substrate, followed by ultrasonic scratching the ceramics surface with a diamond powder suspension to promote the nucleation of diamond during deposition. Diamond films were deposited by the CVD technique assisted by Hot Filament (HFCVD) over Si3N4 drill bits, starting with a layer of microcrystalline diamond that presents high adhesion levels on this ceramics, followed by a layer of NCD that presents low roughness. The coatings were characterized by Scanning Electronic Microscopy (SEM) e Raman spectroscopy. SEM allowed the evaluation of films density and homogeneity and Raman spectroscopy confirmed the quality of the films. Before placing a dental implant in the mandible bone, it is necessary to drill the bone to create a hole of adequate dimension. For the drilling experiments a variable speed drill was used coupled to a Universal Testing Machine. A block of rigid polyurethane foam (ASTM F-1839) was used to simulate the human mandible bone. Cutting speed and the temperature rise during cutting are key parameters for the success of the implant. In the drilling experiments the cutting speed varied in the range 50 to 1400 RPM, and the penetration speed between 7.5 to 30 mm/min. The temperature oscillation during cutting was evaluated by two thermocouples placed in the polymer at different heights. By looking at the results, it is possible to conclude that Si3N4 drill bits diamond coated with a bilayer of MCD/NCD by HFCVD present a better performance, both at low and high cutting speeds, with a smaller increase in temperature, when compared to commercial steel drill bits (AISI 420), used as reference: the applied force is lower in approximately 4 times; the local temperature rise is smaller in about 4 ºC; possibility to cut using low rotation speeds (100 RPM), which will allow the recovery of autogeneous bone; use of high penetration speeds (30 mm/min), that will reduce the duration of the procedure

Filmes de DLC para aplicações biotribológicas

Mestrado em Engenharia Biomédica - BiomateriaisOs filmes de carbono amorfo tipo diamante (DLC) actuam como lubrificantes sólidos em muitas aplicações de desgaste incluindo os implantes articulares da anca e joelho. Entre estes, os filmes de carbono não-hidrogenado podem ser depositados pela técnica de deposição física em fase vapor (PVD) a baixas temperaturas (<325ºC). Estes filmes protectores são quimicamente inertes, possuem elevada dureza e baixo coeficiente de atrito contra polietileno de ultra alto peso molecular (UHMWPE) e outros biomateriais, aumentando assim a qualidade dos implantes articulares. Filmes de DLC foram depositados por sputtering DC em substratos à base de nitreto de silício (Si3N4 monolítico; compósitos Si3N4/TiN e Si3N4/bioglass) visando elevados níveis de adesão. A nanoestrutura do DLC, confirmada pela fraca intensidade da banda D do espectro Raman, combinada com o elevado conteúdo de ligações sp3, comprovado pelo desvio da banda G, levou a um valor de dureza de 16 GPa. Os filmes apresentam-se densos e homogéneos com um valor extremamente baixo de rugosidade (RMS=2.6 nm). Antes de ser implantado no corpo humano, um material tem de provar ser biocompatível. Antes da deposição de DLC, os substratos foram recobertos com uma camada de Si para promover a adesão. Após 35 dias de imersão em SBF, a observação SEM demonstrou que não ocorreu formação de camada apatítica na superfície. A análise química por ICP-AES mostrou que não houve variação na concentração dos iões Ca e P, e que não foram libertados elementos tóxicos na solução. A hidrofobicidade, tensão superficial e carga superficial deste biomaterial foram também avaliadas. A superfície apresentou um valor ligeiramente negativo de carga, como demonstrado pelo valor do potencial zeta de -35.0 ± 1.3 mV para pH=7.4 ± 0.2. A tensão superficial foi de 45.7 mN/m, apresentando uma componente dispersiva predominante da tensão superficial. Os resultados mostram que o revestimento de DLC é tendencialmente hidrofóbico. Os estudos com a linha celular de osteoblastos humanos MG63 não revelaram indícios de citotoxicidade. As células apresentaram morfologia normal e maior crescimento celular, quando comparadas com as placas standard de cultura, mostrando, no entanto, menor adesão celular. Para os ensaios biotribológicos, bolas e discos cerâmicos foram recobertos com filmes de DLC numa primeira etapa para ensaios de deslizamento a seco em movimento recíproco, com pares próprios. Um bias negativo foi aplicado ao compósito condutor Si3N4/TiN, resultando em valores de coeficiente de atrito extremamente baixos(μ=0.015). Numa segunda etapa, placas recobertas com DLC foram testadas contra bolas de UHMWPE. Os testes foram efectuados a seco e lubrificado (SBF). Os resultados preliminares mostram que o coeficiente de atrito mantém-se constante ao longo do ensaio, sem delaminação do DLC. Estes resultados favoráveis permitem recomendar o Si3N4 revestido com DLC como adequado para aplicações em próteses articulares. ABSTRACT: Diamond-like carbon (DLC) films act as solid-film lubricants in many wear resistant applications including articulated implants as hip and knee joints. Among these, non-hydrogenated amorphous carbon films can be grown by Physical Vapour Deposition (PVD) technique at low deposition temperatures (<325ºC). These protective coatings possess chemical inertness, high hardness and low friction coefficient against Ultra High Molecular Weight Polyethylene (UHMWPE) and other biomaterials, thereby improving the quality of articulated implants. In this study, the DLC films were deposited by DC magnetron sputtering over silicon nitride based substrates (bulk Si3N4; Si3N4/TiN and Si3N4/bioglass composites) aiming high adhesion levels. DLC nanostructure, confirmed by the weak intensity of the Raman spectra D band position, combined with significant sp3 content, as depicted by the G band downshift, lead to a hardness value of about 16 GPa. Films are dense and homogeneous in all the deposited area with an extremely low roughness of 2.6 nm (RMS). Before implantation in the human body, a material must prove to be biocompatible. Prior to the DLC deposition, the Si3N4 based ceramics were coated with a Si interlayer to promote adhesion. After 35 days of immersion in Simulated Body Fluid, SBF, the DLC surface showed no signs of apatite layer formation, as observed by SEM. Also, ICP-AES analysis confirmed no variation of the Ca and P ions concentration levels, and no toxic elements released into solution were detected. Hydrophobicity, surface tension and surface charge was also evaluated. The DLC surface is slightly negative charged, has shown by the zeta potential value of -35.0 ± 1.3 mV at pH=7.4 ± 0.2. The surface tension of the DLC coated samples was 45.7mN/m, presenting a dominant dispersive component of the surface tension. Results showed that the DLC coating is quite hydrophobic. Using the MG63 osteoblast-like cells, no evidence of citotoxicity was observed. Cells showed normal morphology and higher cell growth, compared to standard culture plates, although with low cell adhesion. For biotribological assessment, in a first stage Si3N4 ceramic balls and discs were coated with DLC films for self-mated reciprocating dry sliding tests. A negative bias voltage applied to a conductive Si3N4/TiN composite showed a remarkable improvement under the same tribological solicitation, presenting very low friction coefficient values (μ=0.015) during the full duration of the test. In a second stage, DLC-coated Si3N4 ceramics were tested against UHMWPE spheres using a reciprocating ball-on-flat set-up. The sliding occurred under dry and lubricated (SBF) conditions. Preliminary results showed that the friction coefficient is almost constant during the running-in period without delamination of the DLC coating. Based in these favourable results, the DLC-coated Si3N4 biomaterial seems adequate to be used for articular prosthesis development

Vimentin expression and the influence of Matrigel in cell lines of head and neck squamous cell carcinoma

Vimentin is a cytoeskeletal intermediate filament protein commonly observed in mesenchymal cells; however, it can also be found in malignant epithelial cells. It is demonstrated in several carcinomas, such as those of the cervix, breast and bladder, in which it is widely used as a marker of the epithelial to mesenchymal transition that takes place during embryogenesis and metastasis. Vimentin is associated with tumors that show a high degree of invasiveness, being detected in invasion front cells. Its expression seems to be influenced by the tumor microenvironment. The aim of this study was to evaluate vimentin expression in head and neck squamous cell carcinoma (HNSCC) cell lines, and to investigate the contribution of the microenvironment to its expression. HNSCC cell lines (HN6, HN30 and HN31) and an immortalized nontumorigenic cell line (HaCaT) were submitted to a three-dimensional assay with Matrigel. Cytoplasmatic staining of the HN6 cell line cultured without Matrigel and of the HN30 and HN31 cell lines cultured with Matrigel was demonstrated through immunohistochemistry. Western Blotting revealed a significant decrease in vimentin expression for the HN6 cell line and a significant increase for the HN30 and HN31 cell lines cultured with Matrigel. The results suggest that vimentin can be expressed in HNSCC cells and its presence is influenced by the microenvironment of a tumor

An in vitro study showing the three-dimensional microenvironment influence over the behavior of head and neck squamous cell carcinoma

Objectives: The Head and Neck Squamous Cell Carcinoma (HNSCC) ranks sixth worldwide. The mechanisms of growth, invasion and metastasis of this pathology are extensively studied and generally related to specific variations in signaling pathways like the PI3K-Akt; however most of these competent studies have been performed bidimensionally, which may hide important questions. This study sought to analyze the influence of the microenvironment upon the behavior of HNSCC. Study Design: The status of pAkt, NF-?B and Cyclin D1 proteins was accessed through immunofluorescence and western blot methods in HNSCC cell lines originating from tongue, pharynx and metastatic lymph node when submitted to a three-dimensional culture model utilizing a matrix system. A bidimensional culture model (monolayer) was used as control. Results: The HNSCC cell lines cultured three-dimensionally exhibited a growth pattern characterized by small isolated islands, different from the control group. When the three-dimensional model was applied, two of the studied cell lines showed the same expression pattern as the bidimensional model regarding nuclear or cytoplasmatic localization, as well as reduction of all protein levels; however, the cell line originated from tongue, which specially has the epidermal growth factor receptor constitutively activated, demonstrated nuclear translocation of pAkt and also an increase in the levels of Cyclin D1. Conclusions: The results suggest the influence of the microenvironment upon the behavior of HNSCC cells due to the changed expression of proteins related to tumor growth and cellular invasion. Furthermore, intrinsically genetic conditions also played important roles over the cells, despite the culture model employed

Tailored surface energy of stainless steel plate coupons to reduce the adhesion of aluminium silicate deposit

Fouling in heat exchangers not only reduces heat transfer performance significantly, but also causes considerable pressure drop, resulting in higher pumping requirements. It would be much more desirable if surfaces which are inherently less prone towards fouling could be developed. In this paper, autocatalytic Nickel–Phosphorus–Polytetrafluoroethylene (Ni–P–PTFE) composite coatings and modified diamond-like carbon (DLC) coatings were applied to the coupons of the 316L stainless steel plates. The effects of surface energies of the coatings on the adhesion of aluminium silicate fouling were investigated and the best surface energy for which the fouling adhesion is lowest was obtained. The experimental results show that the coating with the most favourable surface energy reduced the adhesion of aluminium silicate deposit by 97%, compared with uncoated stainless steel plate coupons. The anti-fouling mechanism of the coatings was explained with the extended Deryagin, Landau, Verwey and Overbeek (DLVO) theor

Expression of Akt, NF-B and Cyclin D1 proteins in head and neck squamous cell carcinoma cell lines submitted to three-dimensional culture model and an in vitro invasion assay

O carcinoma epidermóide representa mais de 90% das neoplasias malignas de cabeça e pescoço, apresentando taxas elevadas de morbi-mortalidade, porém pouco se sabe sobre as vias de sinalização que estão envolvidas na progressão tumoral. Têm sido relatado na literatura, que alguns estímulos podem ativar a holoenzima PI3K que, por sua vez, desencadeia um processo que induz a fosforilação da proteína Akt (pAkt) que leva a ativação e a translocação do NF-B do citoplasma para o núcleo, onde ocorre a transcrição de genes envolvidos na proliferação e invasão celular. Assim, esse estudo analisou, através dos métodos de Imunofluorescência e Western Blot, a expressão das proteínas pAkt, NF-B e Ciclina D1 em três linhagens de células de carcinoma epidermóide de cabeça e pescoço (HN6, HN30 e HN31) submetidas a cultivo tridimensional e ensaio de invasão (gerando clones invasivos HN6.1, HN30.1 e HN31.1), ambos realizados com Matrigel®. O pAkt apresentou marcação citoplasmática e nuclear nas linhagens celulares HN6, HN30, HN6.1 e na HN30 submetida ao cultivo tridimensional, todavia, as linhagens celulares HN31, HN30.1, HN31.1 e HN6/HN31 cultivadas tridimensionalmente, apresentaram positividade predominantemente nuclear. No caso do NF-B, a localização foi marcadamente citoplasmática em todas as linhagens celulares cultivadas bi ou tridimensionalmente, porém, com exceção da HN31.1, o padrão de marcação foi citoplasmático e nuclear nos clones invasivos. Por fim, a Ciclina D1 exibiu imunopositividade apenas nuclear. A técnica de Western Blot mostrou diminuição nos níveis de expressão das proteínas analisadas quando as células foram cultivadas em Matrigel®, sendo, na maioria das vezes, essa redução estatisticamente significante, exceto no caso da linhagem celular HN6, que apresentou um aumento significativo de Ciclina D1. Os clones invasivos HN6.1 e HN30.1 exibiram elevação significativa dos níveis de expressão de pAkt e NF-B porém, a HN31.1 apresentou aumento de pAkt e discreta diminuição de NF-B, mas ambos os valores não estatisticamente significantes. Em relação à Ciclina D1, houve um aumento dos seus níveis em todas as linhagens invasivas, sendo que apenas na HN6.1 foi estatisticamente significante. Esses resultados mostraram que, nas linhagens celulares avaliadas, quando cultivadas em ambiente tridimensional, a significativa redução dos níveis de expressão de proteínas da via de sinalização PI3K ocorreu devido a uma possível fase adaptativa dessas células ao Matrigel® que seria seguida provavelmente por uma etapa de aumento do potencial proliferativo e posterior transdiferenciação de algumas células para ganho de fenótipo mais agressivo. Além disso, este estudo mostrou a participação da via de sinalização Akt/NF-B/Ciclina D1 no processo de invasão das células de carcinoma epidermóide de cabeça e pescoço (HN6.1 e HN30.1).Squamous cell carcinoma represents more than 90% of the head and neck malignant tumors, with high mortality rates. Nevertheless, the knowledge about signaling pathways involved in tumor progression remains unclear. The relationship between pAkt and NF-B is well established in carcinogenesis. It is known that the activation of PI3K can be induced by some factors what leads to Akt phosphorilation (pAkt). This further event starts an activation cascade that induces NF-B translocation from the cytoplasm into the nucleus where the transcription of genes enrolled in cellular proliferation and invasion will be done. Therefore, this study analyzed the status of pAkt, NF-B and Cyclin D1 proteins by Immunofluorescence and Western Blot methods in three head and neck squamous cell carcinoma cell lines (HN6, HN30 and HN31) submitted to three-dimensional culture model and an in vitro invasion assay (invasive clones HN6.1, HN30.1 e HN31.1), both with Matrigel®. pAkt expression was detected in cytoplasm and nucleus in HN6, HN30, HN6.1 and HN30 cultured with Matrigel®, however, HN31, HN30.1, HN31.1 cell lines and HN6/HN31 submitted to three-dimensional culture model showed nuclear expression. NF-B localization was strongly cytoplasmatic in all cell lines cultured with or without Matrigel®, but, regarding HN31.1, NF-B protein expression was nuclear and cytoplasmatic in the invasive clones. Cyclin D1 was nuclear in all cell lines analyzed. Western blot assays showed a decrease in pAkt, NF-B and Cyclin D1 expression levels in all cells lines in three-dimensional culture model, most of them statistically significant, but It was detected a considerable increase in Cyclin D1 expression in HN6 cultured in threedimensional model. Moreover, HN6.1 and HN30.1 showed a significant enhance in pAkt and NF-B levels but, HN31.1 demonstrated a raise in pAkt and a slight decline in NF-B, both were not statistically significant. Finally, an increase in Cyclin D1 expression levels was illustrated in all cell lines but, only HN6.1 showed a statistic signal. These results suggest that, in the cell lines studied, when cultured in threedimensional model, a noteworthy reduction in expression levels of PI3K signaling pathway proteins happened for the reason that a possibly adaptation phase of these cells to Matrigel® was occurring, in the first moment, but it would be probably followed by an increase proliferative potential stage and subsequent transdifferentiation of some cells that could show, consequently, a more aggressive phenotype. At last, this study revealed the participation of Akt/NF-B/Cyclin D1 signaling pathway in invasion process of head and neck squamous cell carcinoma (HN6.1 and HN30.1)

Biomimétisme et véhicule décarboné : génération de concepts innovants bio-inspirés à partir de la théorie C-K

Le biomimétisme ou conception bio-inspirée est une approche qui propose l'utilisation du vivant en tant que source d'inspiration pour améliorer ou concevoir de nouvelles technologies. Intégrer la conception bio-inspirée au processus d'innovation des entreprises pourrait ainsi permettre la génération de concepts à la fois innovants et durables.Cette thèse, réalisée au sein de Renault avait deux objectifs: comprendre les mécanismes de la conception bio-inspirée et les appliquer à un cas concret dans l'automobile pour stimuler la génération de concepts en rupture.Pour comprendre les mécanismes de la bio-inspiration, nous nous sommes appuyés sur la littérature scientifique ainsi que sur les inventions et concepts bio-inspirés. Pour analyser le raisonnement de conception de ces exemples, nous avons choisi une théorie de la conception, la théorie C-K. Le cadre issu de la théorie C-K nous a permis de proposer un modèle général pour la conception bio-inspirée.Nous avons appliqué ce modèle au champ d'innovation du véhicule décarboné. Ce champ traite des questions liées au développement d'innovations permettant aux véhicules de réduire leur empreinte environnementale, principalement par la réduction des émissions de dioxyde de carbone (CO2), un puissant gaz à effet de serre qui contribue également au phénomène du changement climatique. L'identification des voies où la rupture serait nécessaire a débuté par la réalisation d'un arbre des concepts, à l'aide des connaissances internes disponibles en entreprise auprès des experts leaders. Un travail de réorganisation de ces concepts et la création d'une base de connaissances rassemblant articles scientifiques et expertises sur le sujet des émissions de gaz à effet de serre ont été effectués. Ce travail a permis de cartographier le champ d'innovation du véhicule décarboné. Les véhicules multi-énergies ont été la voie choisie pour la recherche de concepts bio-inspirés.Une recherche générale sur l'énergie dans le vivant nous a conduits à identifier l'énergie dans les cellules animales et particulièrement chez les humains comme une base de connaissances biologiques particulièrement intéressante. L'énergétique humaine possède un certain nombre de propriétés qui pourraient permettre une révision des connaissances sur les véhicules multi-énergie, notamment sur le stockage et la transformation d’énergie. La performance sportive humaine s'est aussi révélée être une base de connaissances intéressante par les différentes techniques utilisées pour les entrainements et en course afin de mieux mobiliser des sources d'énergie.L'application du modèle du processus de bio-inspiration avec C-K nous a conduit à formuler un concept inspiré des observations réalisées sur des coureurs pendant des courses supérieures à 1 500m. En effet, les profils de vitesse enregistrés pour des athlètes indiquent qu'une variation de vitesse est choisie par le coureur pour lui permettre de mieux utiliser ses réserves anaérobies limitées. Pour un véhicule, ceci pourrait impliquer qu'une variation de vitesse pourrait conduire à des meilleurs résultats en termes de consommation de carburant qu'une vitesse stabilisée. Ce concept a été exploré dans cette thèse à l’aide de la réalisation d'essais sur piste et des simulations avec des modèles numériques. Ces explorations montrent le potentiel de ce concept pour des véhicules conventionnels et aussi ses limitations.Ces travaux ouvrent des perspectives pour la gestion d'énergie des véhicules considérant la façon dont l'énergie est produite, stockée et utilisée chez le vivant. Les systèmes énergétiques étudiés par la physiologie humaine représentent un terrain intéressant pour le développement de véhicules adaptables à différents cas d'utilisation. De plus, l'étude du processus de la bio-inspiration a permis d'éclairer les raisons de faire appel à cette démarche et les conditions qui permettraient son application plus systématique dans les processus d'innovation en entreprise.Biologically inspired design, also called bioinspired design, biomimetics or biomimicryproposes the use of Nature, or biological knowledge, as a source of inspiration to improve orconceive new designs. Integrating the biologically inspired design approach into theinnovation process of companies could then allow the generation of more innovative and sustainable concepts.This thesis, realized during three years at a French automaker (Renault) research and development department had two objectives: to understand the mechanisms of the biologically inspired design and to apply this approach to a case belonging to an innovation field of the automotive sector.In order to understand the mechanisms of biologically inspired design we studied theliterature about bio-inspired concepts and inventions.We have chosen a design theory, the C-K theory, to analyse the design process of these literature examples. This allowed us to propose a model for bio-inspiration.We applied this model inspired by the C-K theory to the low carbon vehicle innovation field.This field includes the development of innovations allowing passenger cars to reduce theirenvironmental footprint, mainly the reduction of carbon dioxide (CO2) emissions. Thecarbon dioxide is a greenhouse gas that contributes to the climate change phenomena. Theidentification of the path where concept partitioning is required in this field began with theconstruction of a concepts space, using knowledge of company experts on the subject.Reorganizing these concepts and building a knowledge base on the strategies for CO2 emissions allowed us to map this innovation field. The vehicles with more than oneenergy source, such as electrified internal combustion engine vehicles and hybrid vehicleswere the path chosen for the research of bio-inspired concepts.A research about energy in nature led us to identify the energy in animal cells, particularlythose in humans as an interesting biological knowledge base. Human energy properties suchas cells with more than one kind of energy storage, with at least two metabolic pathways torecharge these stores are interesting to revise the knowledge about energy store andconversion in multi-energy vehicles. Besides, the human sportive performance has appearedto be an interesting knowledge base, as the training techniques and the running techniquesduring a race can influence the way athletes use their energy.These two biological bases have led us to formulate a bio-inspired concept based on therunning patterns observed in runners during races superior to 1500~m. The speed profilesrecorded show a spontaneous speed variation chosen by the runner, in order to better use itslimited anaerobic energy stores. For a vehicle, this could mean that varying its speed couldallow a lower fuel consumption than using a constant speed. This bio-inspired concept wasexplored in this thesis with the realization of tests in a dedicated test track and simulations. These tests show the potential of this concept for conventional vehicles and its limitations.This work opens the way for analysing the vehicle energetics in the light of human energetics.The versatility of human activities could help on the development of vehicles adapting todifferent use cases. Further research could also use the knowledge about the dynamic modelling of energy in vehicles to complete the empirical approaches used to model the human energy management, allowing a betteroptimization of running strategies. The study of the bio-inspiration process using a designtheory also allowed a better comprehension of the reasons for using this approach and of theconditions for successfully applying it in the innovative process of a company