京都大学 / 新制・課程博士 / 博士(工学) / 甲第24614号 / 工博第5120号 / 新制||工||1979(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 邑瀬 邦明, 教授 宇田 哲也, 教授 作花 哲夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Human mobility is central to socioeconomic interactions in modern society. Unprecedented reliance on individual transportation has resulted in widespread challenges globally, including congestion, emissions, and socioeconomic inequalities. These issues are anticipated to worsen with climate change, presenting a significant risk to human civilization. Notably, human mobility accounts for over 15% of total carbon emissions, with the bulk stemming from private transportation. Therefore, there is a pressing need to transition to sustainable alternatives like public transport to address these challenges effectively. Public transport comprises a complex system with multiple interacting parts, including users, drivers, service providers, and evolving urban infrastructure. The interactions among these elements give rise to multiple self-organized states, which play a pivotal role in determining the attractiveness and efficiency of public transport systems. In this thesis, we combine tools from network dynamics, statistical physics, nonlinear dynamics, transport science, and data analysis to understand emergent behavior in public transport worldwide. Public transport infrastructure highlights the disparities in cities across the globe. Developed countries in the Global North generally feature centrally organized formal transport systems, while developing nations in the Global South are served by informal transport operated by private individuals. In our study of complex self-organized states within both formal and informal transport, we explore how self-organization enhances mode attractiveness in some contexts whereas it may reduce ridership in others. We find that in urbanizing cities with formal transport, the interaction between users and service providers can lead to sub-optimal transport outcomes. With the rise of app-based technologies, on-demand transport services like bike taxis are becoming increasingly popular within cities in the Global South. Our results suggest that as congestion grows, a transition may occur, leading users to shift from shared transport to single-passenger options like bike taxis. Finally, our analysis of transport systems in cities across the globe shows that informal transport often self-organizes into more efficient route structures compared to formal transport, indicating that lessons from these informal systems could lead to the improvement of formal transport systems. Our findings provide a foundation for developing intervention strategies to enhance public transportation, by bridging the gap between physics, graph theory, transportation research, data science, and public policy. The results offer valuable insights into reducing congestion and emissions, contributing to a more sustainable and livable urban future, while highlighting the importance of further studies into the collective dynamics of human mobility systems. / Die menschliche Mobilität ist für die sozioökonomischen Interaktionen in der modernen Gesellschaft von zentraler Bedeutung. Die beispiellose Abhängigkeit vom Individualverkehr hat weltweit zu weitreichenden Problemen geführt, darunter Verkehrsstaus, Emissionen und sozioökonomischen Ungleichheiten. Es wird erwartet, dass sich diese Probleme mit dem Klimawandel noch verschärfen werden, was ein erhebliches Risiko für die menschliche Zivilisation darstellt. Vor allem die menschliche Mobilität ist für über 15% der gesamten Kohlenstoffemissionen verantwortlich, wobei der Großteil auf den Individualverkehr entfällt. Daher besteht die dringende Notwendigkeit, auf nachhaltige Alternativen wie den öffentlichen Verkehr umzusteigen, um diesen Herausforderungen wirksam zu begegnen. Der öffentliche Verkehr ist ein komplexes System mit zahlreichen interagierenden Komponenten, darunter Nutzer, Fahrer, Dienstleister und die sich entwickelnde städtische Infrastruktur. Die Wechselwirkungen zwischen diesen Elementen führen zu zahlreichen selbstorganisierten Zuständen, die eine zentrale Rolle bei der Bestimmung der Attraktivität und Effizienz von öffentlichen Verkehrssystemen spielen. In dieser Arbeit kombinieren wir Werkzeuge aus der Netzwerkdynamik, der statistischen Physik, der nichtlinearen Dynamik, der Verkehrswissenschaft und der Statistik, um das emergente Verhalten im öffentlichen Verkehr weltweit zu verstehen. Die Infrastruktur des öffentlichen Verkehrs verdeutlicht die Ungleichheiten in den Städten der Welt. In den Industrieländern des globalen Nordens gibt es in der Regel zentral organisierte formale Verkehrssysteme, während in den Entwicklungsländern des globalen Südens der informelle Verkehr von Privatpersonen betrieben wird. In unserer Studie über komplexe selbstorganisierte Zustände sowohl im formellen als auch im informellen Verkehr untersuchen wir, wie die Selbstorganisation die Attraktivität der Verkehrsmittel in einigen Kontexten erhöht, während sie in anderen die Fahrgastzahlen verringern kann. Wir stellen fest, dass in Städten mit formellem Verkehr die Interaktion zwischen Nutzern und Dienstleistern zu suboptimalen Verkehrsergebnissen führen kann. Mit dem Aufkommen von App-basierten Technologien werden On-Demand-Verkehrsdienste wie Fahrradtaxis in Städten des globalen Südens immer beliebter. Unsere Ergebnisse deuten darauf hin, dass mit zunehmender Überlastung ein Übergang stattfinden kann, der die Nutzer dazu veranlasst, von gemeinsam genutzten Verkehrsmitteln auf Einzelpersonenoptionen wie Fahrradtaxis umzusteigen. Schließlich zeigt unsere Analyse von Verkehrssystemen in Städten auf der ganzen Welt, dass sich der informelle Verkehr im Vergleich zum formellen Verkehr oft selbst in effizienteren Routenstrukturen organisiert, was darauf hindeutet, dass Lehren aus diesen informellen Systemen zur Verbesserung formeller Verkehrssysteme führen könnten. Unsere Ergebnisse bieten eine Grundlage für die Entwicklung von Interventionsstrategien zur Verbesserung des öffentlichen Verkehrs, indem sie die Lücke zwischen Physik, Graphentheorie, Verkehrsforschung, Datenwissenschaft und öffentlicher Politik schließen. Die Ergebnisse bieten wertvolle Einblicke in die Reduzierung von Staus und Emissionen und tragen so zu einer nachhaltigeren und lebenswerteren urbanen Zukunft bei.

This study is the result of a two-year long minor field study project of informal settlements in Buenos Aires, Argentina. The aim was to analyse the concept of disaster resilience by describing possible contemporary complications in both theory and practice related to resilience and risks of informal settlements in Buenos Aires. For this reason I have applied the theoretical concept of resilience used by United Nations International Strategy for Disaster Reduction (UNISDR). The research has been conducted in two local settings of informal settlements by using a qualitative case study approach of semi-structured interviews and observations. The chosen area of empirics has been limited to local voluntary and political organisations in a context of self-organization were all chosen interviewees have some relation to either projects or organizations in the area. The results show that local context of functionality depends on different political strategies that can either restrict or assist the process of resilience, which can occur on both individual and collective levels of community. In this context resistance to natural hazards becomes contradictive in absence of prevention when resilience is achieved without even touching high levels of vulnerability such as drugs and violence. In this setting United Nations stands before a change of paradigms in either continuing to manage disasters or change focus to manage underlying drivers of risks. / Este estudio es el resultado de un proyecto de dos años de un estudio de campo menor sobre los asentamientos informales en Buenos Aires, Argentina. El propósito fue analizar el concepto de resiliencia de los desastres, describiendo las posibles complicaciones contemporáneos tanto en la teoría y la práctica, en relación con la resiliencia y los riesgos de los asentamientos informales en Buenos Aires. Por esta razón he aplicado el concepto teórico de la resiliencia utilizada por la Estrategia Internacional para la Reducción de Desastres de las Naciones Unidas (UNISDR). La investigación se ha realizado en dos configuraciones locales de los asentamientos informales, mediante el uso de un enfoque de estudio de caso cualitativo de observaciones y entrevistas semi-estructuradas. El área elegida de análisis empírico se ha limitado a las organizaciones locales de voluntarios y políticos en un contexto de auto-organización, donde todos los entrevistados han sido elegidos porque tienen alguna relación con cualquiera de los proyectos u organizaciones de la zona. Los resultados muestran que el contexto local de la funcionalidad depende de diferentes estrategias políticas que pueden restringir o asistir al proceso de resiliencia, esto puede ocurrir en ambos niveles individuales y colectivos de la comunidad. En este contexto, la resistencia a las amenazas naturales se vuelve contradictorio por la ausencia de la prevención, cuando se alcanza la capacidad de resiliencia sin tocar los altos niveles de vulnerabilidad, como las drogas y la violencia. En este escenario las Naciones Unidas se encuentra ante un cambio de paradigma, ya sea continuar para gestionar los desastres o cambiar de enfoque para gestionar los  factores subyacentes de los riesgos. / Minor Field Study

From a visual standpoint it is often easy to point out whether a system is considered to be self-organizing or not, though a quantitative approach would be more helpful. Information theory, as introduced by Shannon, provides the right tools not only quantify self-organization, but also to investigate it in relation to the information processing performed by individual agents within a collective. This thesis sets out to introduce methods to quantify spatial self-organization in collective systems in the continuous domain as a means to investigate morphogenetic processes. In biology, morphogenesis denotes the development of shapes and form, for example embryos, organs or limbs. Here, I will introduce methods to quantitatively investigate shape formation in stochastic particle systems. In living organisms, self-organization, like the development of an embryo, is a guided process, predetermined by the genetic code, but executed in an autonomous decentralized fashion. Information is processed by the individual agents (e.g. cells) engaged in this process. Hence, information theory can be deployed to study such processes and connect self-organization and information processing. The existing concepts of observer based self-organization and relevant information will be used to devise a framework for the investigation of guided spatial self-organization. Furthermore, local information transfer plays an important role for processes of self-organization. In this context, the concept of synergy has been getting a lot attention lately. Synergy is a formalization of the idea that for some systems the whole is more than the sum of its parts and it is assumed that it plays an important role in self-organization, learning and decision making processes. In this thesis, a novel measure of synergy will be introduced, that addresses some of the theoretical problems that earlier approaches posed.

Ce travail est dédié à l'étude du comportement agrégatif chez la fourmi Lasius niger afin de caractériser le phénomène au niveau collectif, par l'étude de la dynamique et de la structure agrégative, et au niveau des mécanismes sous-tendant le phénomène par l’analyse des comportements individuels des fourmis. Nous avons montré expérimentalement et vérifié par la modélisation que l’agrégation est essentiellement liée à un phénomène amplificateur : plus l’agrégat est de grande taille, plus les fourmis y restent longtemps. Nos résultats indiquent que le niveau d’agrégation et la structure formée sont dépendants de plusieurs facteurs comme la densité et la surface disponible : une évolution de la structure agrégative des nourrices est observée, passant d’un grand agrégat stable pour les petites densité-surface à plusieurs agrégats à hiérarchie de taille moins marquée pour les grandes densité-surface. L’agrégation est aussi influencée par la caste éthologique des fourmis, les nourrices s’agrégeant en un agrégat stable de grande taille, les fourrageuses en quelques petits agrégats instables. Cette différence s’explique par une probabilité plus faible des fourrageuses à rester dans l’agrégat. Dans les groupes mixtes, les fourmis gardent les caractères propres à leur caste, ne semblant pas influencées par la caste de l’individu rencontré. Enfin, l’agrégation diffère quantitativement mais non qualitativement selon l’espèce utilisée : nos études sur Crematogaster scutellaris, Atta sexdens-rubropilosa, Solenopsis invicta, Pheidole pallidula, Linepithema humile, Myrmica rubra et M. ruginodis montrent une grande variété de réponses, en nombre et en taille d’agrégats, qui est aussi fonction de la caste de fourmis utilisée. Une constance, cependant, apparaît dans nos résultats : les nourrices paraissent mieux s’agréger que les fourrageuses. Ces résultats sont discutés en fonction de leur valeur adaptative pour la colonie et d’un lien possible avec la distribution spatiale des individus à l’intérieur du nid./This work is dedicated to the study of the aggregative behaviour in the ant Lasius niger in order to characterize the phenomenon at the collective level by a study of the dynamic and the collective structure, and at the individual level to understand the mechanisms underlying the phenomenon. We demonstrated experimentally and verified by a model that aggregation is essentially due to an amplificatory phenomenon: the greater the ant numbers in a cluster, the greater the time spent by an ant inside this cluster. Our results indicate that the aggregation level and the form of the collective structure depend on different factors such as the density and the surface: for brood-tenders, an evolution of the aggregative structure is observed shifting from a large stable aggregate for low density-surface to several smaller clusters with a less pronounced hierarchical size for the greater density-surface. Aggregation is also influenced by the ethological caste of the ant: the brood-tenders aggregate in a big stable cluster and the foragers in some unstable clusters. This difference is explained by a smaller probability of foragers to stay inside the cluster. In mixed groups, ants keep their own characteristics, not appearing to be influenced by the caste of the individual encountered. Finally, aggregation is influenced by the ant species: our studies on Crematogaster scutellaris, Atta sexdens-rubropilosa, Solenopsis invicta, Pheidole pallidula, Linepithema humile, Myrmica rubra and M. ruginodis show us a large variety of responses, in the number and the size of the clusters, which is also a function of the caste of ants which is used. A constant result, nevertheless, appears in our results: brood-tenders seem to aggregate better than foragers. These results are discussed in term of their adaptive value for the colony and a possible link with the spatial distribution of ants inside the nest.

<p>The behavior of fibers suspended in a flow between two counter-rotating discs has been studied experimentally. This is inspired by the refining process in the papermaking process where cellulose fibers are ground between discs in order to change performance in the papermaking process and/or qualities of the final paper product.</p><p>To study the fiber behavior in a counter-rotating flow, an experimental set-up with two glass discs was built. A CCD-camera was used to capture images of the fibers in the flow. Image analysis based on the concept of steerable filters extracted the position and orientation of the fibers in the plane of the discs. Experiments were performed for gaps of 0.1-0.9 fiber lengths, and for equal absolute values of the angular velocities for the upper and lower disc. The aspect ratios of the fibers were 7, 14 and 28.</p><p>Depending on the angular velocity of the discs and the gap between them, the fibers were found to organize themselves in fiber trains. A fiber train is a set of fibers positioned one after another in the tangential direction with a close to constant fiber-to-fiber distance. In the fiber trains, each individual fiber is aligned in the radial direction (i.e. normal to the main direction of the train).</p><p>The experiments show that the number of fibers in a train increases as the gap between the discs decreases. Also, the distance between the fibers in a train decreases as the length of the train increases, and the results for short trains are in accordance with previous numerical results in two dimensions.Furthermore, the results of different aspect ratios imply that there are three-dimensional fiber end-effects that are important for the forming of fiber trains.</p>

<p>Advanced architectures for cluster-based services that have been recently proposed allow for service differentiation, server overload control and high utilization of resources. These systems, however, rely on centralized functions, which limit their ability to scale and to tolerate faults. In addition, they do not have built-in architectural support for automatic reconfiguration in case of failures or addition/removal of system components.</p><p>Recent research in peer-to-peer systems and distributed management has demonstrated the potential benefits of decentralized over centralized designs: a decentralized design can reduce the configuration complexity of a system and increase its scalability and fault tolerance.</p><p>This research focuses on introducing self-management capabilities into the design of cluster-based services. Its intended benefits are to make service platforms dynamically adapt to the needs of customers and to environment changes, while giving the service providers the capability to adjust operational policies at run-time.</p><p>We have developed a decentralized design that efficiently allocates resources among multiple services inside a server cluster. The design combines the advantages of both centralized and decentralized architectures. It allows associating a set of QoS objectives with each service. In case of overload or failures, the quality of service degrades in a controllable manner. We have evaluated the performance of our design through extensive simulations. The results have been compared with performance characteristics of ideal systems.</p>

Molecular-based quantum cellular automata (m-QCA), as an extension of quantum-dot QCAs, offer a novel alternative in which binary information can be encoded in the molecular charge configuration of a cell and propagated via nearest-neighbor Coulombic cell-cell interactions. Appropriate functionality of m-QCAs involves a complex relationship between quantum mechanical effects, such as electron transfer processes within the molecular building blocks, and electrostatic interactions between cells. In the first part of this document, the influence of structural distortions in single m-QCA is addressed within a minimal model using an diabatic-to-adiabatic transformation. Thus, it is shown that even small changes of the classical square geometry between driver and target cells, such as those induced by distance variations or shape distortions, can make cells respond to interactions in a far less symmetric fashion, modifying and potentially impairing the expected computational behavior of the m-QCA. The model has been further extended to consider time-dependent external electric fields in which a special emphasis is given to the profiles in which this external parameter can interact with the associated molecular complex. The results of the model have been validated by a direct comparison with first-principle calculations allowing to conclude the plausibility to induce the intra-molecular charge transfer process in a controllable manner via the interaction with the external electric field. The influence played by the electric field profile in the response of the molecular complex is also investigated. The results suggests a major role played by this variable in terms of the time length in which the intra-molecular charge transfer can be observed. In the second part, first-principle theoretical calculations of the self-assembly properties and electronic structure of Ferrocene-functionalized complexes have been carried out. Hence, five different molecular complexes which offer a potential playground to realistic implement the m-QCA paradigm have been investigated. The main emphasis is given to study the interaction between localized charge-carrier molecular states and the delocalized surface states. The results of these calculations demonstrate the possibility to obtain real systems in which intra-molecular charge localization can be combined with self-assembly scaffolding and absorbed on either Highly oriented pyrolytic graphite (HOPG) or metallic-surfaces. Finally, the validation of these findings is carried out via comparison with accesible experimental results and opening the gate to plausible strategies where the paradigm can be implemented.

Nous apprenons très jeunes une quantité de règles nous permettant d'interagir avec d'autres personnes: des conventions sociales. Elles diffèrent des autres types d'apprentissage dans le sens où les premières personnes à les avoir utilisées n'ont fait qu'un choix arbitraire parmi plusieurs alternatives possibles: le côté de la route où conduire, la forme d'une prise électrique, ou inventer de nouveaux mots. À cause de celà, lorsqu'une nouvelle convention se crée au sein d'une population d'individus interagissant entre eux, de nombreuses alternatives peuvent apparaître et conduire à une situation complexe où plusieurs conventions équivalentes coexistent en compétition. Il peut devenir difficile de les retenir toutes, comment faisons-nous pour trouver un accord efficacement ? Nous exerçons communément un contrôle actif sur nos situations d'apprentissage, en par exemple sélectionnant des activités qui ne soient ni trop simples ni trop complexes. Il a été montré que ce type de comportement, dans des cas comme l'apprentissage sensori-moteur, aide à apprendre mieux, plus vite, et avec moins d'exemples. Est-ce que de tels mécanismes pourraient aussi influencer la négociation de conventions sociales? Le lexique est un exemple particulier de convention sociale: quels mots associer avec tel objet ou tel sens? Une classe de modèles computationels, les Language Games, montrent qu'il est possible pour une population d'individus de construire un langage commun via une série d'interactions par paires. En particulier, le modèle appelé Naming Game met l'accent sur la formation du lexique reliant mots et sens, et montre une typique explosion de la complexité avant de commencer à écarter les conventions synonymes ou homonymes et arriver à un consensus. Dans cette thèse, nous introduisons l'idée de l'apprentissage actif et du contrôle actif de la croissance de la complexité dans le Naming Game, sous la forme d'une politique de choix du sujet de conversation, applicable à chaque interaction. Différentes stratégies sont introduites, et ont des impacts différents sur à la fois le temps nécessaire pour converger vers un consensus et la quantité de mémoire nécessaire à chaque individu. Premièrement, nous limitons artificiellement la mémoire des agents pour éviter l'explosion de complexité locale. Quelques stratégies sont présentées, certaines ayant des propriétés similaires au cas standard en termes de temps de convergence. Dans un deuxième temps, nous formalisons ce que les agents doivent optimiser, en se basant sur une représentation de l'état moyen de la population. Deux stratégies inspirées de cette notion permettent de limiter les besoins en mémoire sans avoir à contraindre le système, et en prime permettent de converger plus rapidement. Nous montrons ensuite que la dynamique obtenue est proche d'un comportement théorique optimal, exprimé comme une borne inférieure au temps de convergence. Finalement, nous avons mis en place une expérience utilisateur en ligne sous forme de jeu pour collecter des données sur le comportement d'utilisateurs réels placés dans le cadre du modèle. Les résultats suggèrent qu'ils ont effectivement une politique active de choix de sujet de conversation, en comparaison avec un choix aléatoire.Les contributions de ce travail de thèse incluent aussi une classification des modèles de Naming Games existants, et un cadriciel open-source pour les simuler. / Social conventions are learned mostly at a young age, but are quite different from other domains, like for example sensorimotor skills. The first people to define conventions just picked an arbitrary alternative between several options: a side of the road to drive on, the design of an electric plug, or inventing a new word. Because of this, while setting a new convention in a population of interacting individuals, many competing options can arise, and lead to a situation of growing complexity if many parallel inventions happen. How do we deal with this issue?Humans often exhert an active control on their learning situation, by for example selecting activities that are neither too complex nor too simple. This behavior, in cases like sensorimotor learning, has been shown to help learn faster, better, and with fewer examples. Could such mechanisms also have an impact on the negotiation of social conventions ? A particular example of social convention is the lexicon: which words we associated with given meanings. Computational models of language emergence, called the Language Games, showed that it is possible for a population of agents to build a common language through only pairwise interactions. In particular, the Naming Game model focuses on the formation of the lexicon mapping words and meanings, and shows a typical burst of complexity before starting to discard options and find a final consensus. In this thesis, we introduce the idea of active learning and active control of complexity growth in the Naming Game, in the form of a topic choice policy: agents can choose the meaning they want to talk about in each interaction. Several strategies were introduced, and have a different impact on both the time needed to converge to a consensus and the amount of memory needed by individual agents. Firstly, we artificially constrain the memory of agents to avoid the local complexity burst. A few strategies are presented, some of which can have similar convergence speed as in the standard case. Secondly, we formalize what agents need to optimize, based on a representation of the average state of the population. A couple of strategies inspired by this notion help keep the memory usage low without having constraints, but also result in a faster convergence process. We then show that the obtained dynamics are close to an optimal behavior, expressed analytically as a lower bound to convergence time. Eventually, we designed an online user experiment to collect data on how humans would behave in the same model, which shows that they do have an active topic choice policy, and do not choose randomly. Contributions from this thesis also include a classification of the existing Naming Game models and an open-source framework to simulate them.

Essa tese de doutoramento utiliza a auto-organização dos filmes finos layer-by-layer (LbL), auto-organização por alcanotióis mistas (SAMmix) e monocamada de Langmuir no desenvolvimento de dispositivos e novas metodologias para aplicações em nanomedicina. Foram desenvolvidos e aplicados biossensores utilizando as técnicas de LbL e SAM. Dentre os biossensores construídos está o sensor para óxido nítrico (NO&bull;), que é de grande importância no sistema fisiológico. O sensor foi construído por meio da modificação de ultramicroeletrodos de fibra de carbono pela técnica LbL. A caracterização do sensor foi realizada por voltametrias e espectroscopias de impedância eletroquímica. Os resultados revelaram que a difusão de NO&bull; é dependente do número de bicamadas empregadas e da disposição das moléculas no filme. O sensor com arquitetura CF-(PAMAM/NiTsPc), fibra de carbono (CF), ftalocianina de níquel tetrasulfonada (NiTsPc) e dendrímero poliamidoamina (PAMAM), apresentou o melhor sinal analítico. Além disso, foi analisada a detecção de NO&bull; com interferentes como nitrito, nitrato, peróxido de hidrogênio, ácido ascórbico, dopamina, epinefrina e a norepinefrina. Os resultados mostraram alta seletividade devido à utilização do dendrímero PAMAM. O segundo biossensor utilizou a enzima acetilcolinesterase imobilizada em monocamadas auto-organizadas mistas (SAMmix) de alcanotióis. A detecção eletroquímica mostrou-se altamente sensível, uma vez que não há o uso do glutaraldeído como agente reticulante. Com essa plataforma foi possível desenvolver um biossensor de acetilcolina estável e robusto, sendo calculado o valor de Km app = 0,46x10-3 mol L-1, limite de detecção LD=3,32x10-10 mol L-1 e limite de quantificação LQ=1,11x10-9 mol L-1, valores inferiores aos encontrados na literatura, ressaltando a eficiencia da nova plataforma. Seguindo a mesma idéia de auto-organização, foram realizados estudos de nanotoxicidade utilizando modelos de membrana a partir de filmes de Langmuir. O principal objetivo foi elucidar a ação dos nanotubos de carbono (SWCNT), PAMAM e do nanocomplexo entre os dois materiais (SWCNT-PAMAM) nas membranas celulares, a nível molecular, usando um sistema modelo de membrana. A penetração de SWCNT e dos nanocomplexos em monocamadas lipídicas foi estudada utilizando microscopia de ângulo de Brewster (BAM) simultaneamente com cinética de absorção e pressão de superfície. Os resultados confirmaram a interação entre os nanomateriais e a membrana, indicando que a presença dos nanomateriais afeta o empacotamento dos lipídios. Foram realizados ainda estudos de citotoxicidade dos mesmos nanomateriais em sistemas celulares in vitro. Os resultados de citometria, proliferação celular, morfologia e inibição de adesão apresentaram-se evidenciaram que a combinação entre SWCNT e PAMAM, proporciona um maior índice de toxicidade em relação ao SWCNT, um comportamento diferente do que relatado nos componentes individuais. A toxicidade de nanocomplexos de SWCNT-PAMAM e de seus componentes individuais podem estar fortemente ligados ao tipo de material e como estes estão disponíveis no meio de cultura. Os estudos contidos nessa tese mostram a versatilidade dos filmes finos em sistemas auto-organizados e biomiméticos, e podem ser relevantes para o avanço de pesquisas sobre interação de nanomateriais e biossistemas. / In this thesis we employed the concept of self-organization, including the layer-by-layer (LbL) technique, alkanethiols self-assembled monolayers (SAMmix) and Langmuir monolayers, to develop new methods for materials and devices manipulation for application in nanomedicine. Two different types of biosensors were developed. The first one was based on the LbL technique to detect nitric oxide (NO&bull;), which is of great importance in the medicine. The second biosensor was based on SAM monolayers supporting acetylcholinesterase for pesticide monitoring. The NO&bull; was constructed by modified carbon fiber (CF) assembled with nickel phtalocyanine tetrasulfonade (NiTsPc) and polyamidoamine dendrimer (PAMAM) in the form of ultramicroelectrodes (UMEs) by the LbL technique. The sensor was characterized using differential pulse voltammetry and electrochemical impedance spectroscopy. The results showed that NO&bull; diffusion is dependent on the number of bilayers employed and the arrangement of molecules in the film. The sensor architecture with CF-(PAMAM/NiTsPc) presented the best analytical signal. In addition, we analyzed the detection of interfering with NO&bull; as nitrite, nitrate, hydrogen peroxide, ascorbic acid, dopamine, epinephrine and norepinephrine. The results showed high selectivity due to the use of PAMAM dendrimer as selective layer. The second biosensor used the enzyme acetylcholinesterase immobilized on SAMmix. The electrochemical detection of carbaryl was highly sensitive, since there is no use of glutaraldehyde as crosslinking agent. Using acetylcholine as a probe, Kmapp value was determined at 0.46x10-3 mol L-1, with detection limit of 3.32x10-10 mol L-1 and quantification limit of 1.11x10-9 mol L-1, values lower than those found in the literature, highlighting the efficiency of the new platform. Langmuir films made of lipids were employed as cell membrane models, in order to investigate the interactions between single-wall carbon nanotubes (SWCNT), PAMAM and their nanocomplex (SWCNT-PAMAM) at the molecular level. The interation of SWCNT and nanocomplexes in lipid monolayers was studies using Brewster angle microscopy (BAM) in conjunction with absorption kinetics and surface pressure. The results confirmed the interaction between nanomaterials and the membrane, indicating that the presence of nanomaterials affects the packing of the lipids. Cytotoxicity studies were also employed to investigate the interaction of nanomaterials in in vitro cell systems. The results of flow cytometry, cell proliferation, morphology and inhibition of adhesion revealed the toxicological aspects of the materials, demonstrating a higher toxicity to the nanocomplex, compared to SWCNT, differently of the individual components. The toxicity of SWCNT nanocomplex and its individual components can be related to the type of material and how these materials are available in the culture medium. The studies in this thesis show the versatility of self-assembly thin films on biomimetic systems and may be relevant to the advance of research on the interaction of nanomaterials and biosystems.