Supramolecular functional assemblies with photo or chemical addressability

Supramolecular self-assembly represents a key technology for the spontaneous construction of nanoarchitectures and for the fabrication of materials with enhanced physical and chemical properties. In addition, a significant asset of supramolecular self-assemblies rests on their reversible formation, thanks to the kinetic lability of their non-covalent interactions. This dynamic nature can be exploited for the development of “self-healing” and “smart” materials towards the tuning of their functional properties upon various external factors. One particular intriguing objective in the field is to reach a high level of control over the shape and size of the supramolecular architectures, in order to produce well-defined functional nanostructures by rational design. In this direction, many investigations have been pursued toward the construction of self-assembled objects from numerous low-molecular weight scaffolds, for instance by exploiting multiple directional hydrogen-bonding interactions. In particular, nucleobases have been used as supramolecular synthons as a result of their efficiency to code for non-covalent interaction motifs. Among nucleobases, guanine represents the most versatile one, because of its different H-bond donor and acceptor sites which display self-complementary patterns of interactions. Interestingly, and depending on the environmental conditions, guanosine derivatives can form various types of structures. Most of the supramolecular architectures reported in this Thesis from guanosine derivatives require the presence of a cation which stabilizes, via dipole-ion interactions, the macrocyclic G-quartet that can, in turn, stack in columnar G-quadruplex arrangements. In addition, in absence of cations, guanosine can polymerize via hydrogen bonding to give a variety of supramolecular networks including linear ribbons. This complex supramolecular behavior confers to the guanine-guanine interactions their upper interest among all the homonucleobases studied. They have been subjected to intense investigations in various areas ranging from structural biology and medicinal chemistry – guanine-rich sequences are abundant in telomeric ends of chromosomes and promoter regions of DNA, and are capable of forming G-quartet based structures– to material science and nanotechnology. This Thesis, organized into five Chapters, describes mainly some recent advances in the form and function provided by self-assembly of guanine based systems. More generally, Chapter 4 will focus on the construction of supramolecular self-assemblies whose self-assembling process and self-assembled architectures can be controlled by light as external stimulus. Chapter 1 will describe some of the many recent studies of G-quartets in the general area of nanoscience. Natural G- quadruplexes can be useful motifs to build new structures and biomaterials such as self-assembled nanomachines, biosensors, therapeutic aptamer and catalysts. In Chapters 2-4 it is pointed out the core concept held in this PhD Thesis, i.e. the supramolecular organization of lipophilic guanosine derivatives with photo or chemical addressability. Chapter 2 will mainly focus on the use of cation-templated guanosine derivatives as a potential scaffold for designing functional materials with tailored physical properties, showing a new way to control the bottom-up realization of well-defined nanoarchitectures. In section 2.6.7, the self-assembly properties of compound 28a may be considered an example of open-shell moieties ordered by a supramolecular guanosine architecture showing a new (magnetic) property. Chapter 3 will report on ribbon-like structures, supramolecular architectures formed by guanosine derivatives that may be of interest for the fabrication of molecular nanowires within the framework of future molecular electronic applications. In section 3.4 we investigate the supramolecular polymerizations of derivatives dG 1 and G 30 by light scattering technique and TEM experiments. The obtained data reveal the presence of several levels of organization due to the hierarchical self-assembly of the guanosine units in ribbons that in turn aggregate in fibrillar or lamellar soft structures. The elucidation of these structures furnishes an explanation to the physical behaviour of guanosine units which display organogelator properties. Chapter 4 will describe photoresponsive self-assembling systems. Numerous research examples have demonstrated that the use of photochromic molecules in supramolecular self-assemblies is the most reasonable method to noninvasively manipulate their degree of aggregation and supramolecular architectures. In section 4.4 we report on the photocontrolled self-assembly of modified guanosine nucleobase E-42: by the introduction of a photoactive moiety at C8 it is possible to operate a photocontrol over the self-assembly of the molecule, where the existence of G-quartets can be alternately switched on and off. In section 4.5 we focus on the use of cyclodextrins as photoresponsive host-guest assemblies: αCD–azobenzene conjugates 47-48 (section 4.5.3) are synthesized in order to obtain a photoresponsive system exhibiting a fine photocontrollable degree of aggregation and self-assembled architecture. Finally, Chapter 5 contains the experimental protocols used for the research described in Chapters 2-4.

Struktur-Eigenschafts-Beziehungen flüssigkristalliner hyperverzweigter Polymere

Auf dem Gebiet der polymeren Flüssigkristallforschung sind definierte Systeme unerlässlich. Im Gegensatz zu Dendrimeren und linearen Polymeren, standen hyperverzweigte Materialien mit enger Molekulargewichtsverteilung lange Zeit nicht zur Verfügung. Hyperverzweigte Polymere besitzen die gleichen Vorteile wie Dendrimere; hohe Endgruppendichte und niedrige Viskositäten, jedoch sind hyperverzweigte Polymere einfacher und in größeren Mengen zugänglich, was sie für industrielle Anwendungen interessant macht. Mit der Entwicklung der Synthese von hyperverzweigten Polymeren enger Molekulargewichtsverteilung durch Frey et al. wurde der Grundstein für hyperverzweigte LC-Materialien gelegt. Im Rahmen diese Dissertation wurden Synthesewege zur Darstellung hyperverzweigter LC-Materialien entwickelt und ihr Phasenverhalten sowie die Überstrukturbildung in Abhängigkeit verschiedener struktureller Parameter untersucht. Die erarbeiteten Struktur-Eigenschafts-Beziehungen ermöglichen die Synthese flüssigkristalliner hyperverzweigter Polymere mit spezifischen Eigenschaften für Anwendungen in der Display-Technologie oder auf dem Gebiet selbstorganisierender Systeme.

Modeling and simulation of a synthetic genetic circuit that implements a multicelled behavior in a growing microcolony of E. coli

Synthetic Biology is a relatively new discipline, born at the beginning of the New Millennium, that brings the typical engineering approach (abstraction, modularity and standardization) to biotechnology. These principles aim to tame the extreme complexity of the various components and aid the construction of artificial biological systems with specific functions, usually by means of synthetic genetic circuits implemented in bacteria or simple eukaryotes like yeast. The cell becomes a programmable machine and its low-level programming language is made of strings of DNA. This work was performed in collaboration with researchers of the Department of Electrical Engineering of the University of Washington in Seattle and also with a student of the Corso di Laurea Magistrale in Ingegneria Biomedica at the University of Bologna: Marilisa Cortesi. During the collaboration I contributed to a Synthetic Biology project already started in the Klavins Laboratory. In particular, I modeled and subsequently simulated a synthetic genetic circuit that was ideated for the implementation of a multicelled behavior in a growing bacterial microcolony. In the first chapter the foundations of molecular biology are introduced: structure of the nucleic acids, transcription, translation and methods to regulate gene expression. An introduction to Synthetic Biology completes the section. In the second chapter is described the synthetic genetic circuit that was conceived to make spontaneously emerge, from an isogenic microcolony of bacteria, two different groups of cells, termed leaders and followers. The circuit exploits the intrinsic stochasticity of gene expression and intercellular communication via small molecules to break the symmetry in the phenotype of the microcolony. The four modules of the circuit (coin flipper, sender, receiver and follower) and their interactions are then illustrated. In the third chapter is derived the mathematical representation of the various components of the circuit and the several simplifying assumptions are made explicit. Transcription and translation are modeled as a single step and gene expression is function of the intracellular concentration of the various transcription factors that act on the different promoters of the circuit. A list of the various parameters and a justification for their value closes the chapter. In the fourth chapter are described the main characteristics of the gro simulation environment, developed by the Self Organizing Systems Laboratory of the University of Washington. Then, a sensitivity analysis performed to pinpoint the desirable characteristics of the various genetic components is detailed. The sensitivity analysis makes use of a cost function that is based on the fraction of cells in each one of the different possible states at the end of the simulation and the wanted outcome. Thanks to a particular kind of scatter plot, the parameters are ranked. Starting from an initial condition in which all the parameters assume their nominal value, the ranking suggest which parameter to tune in order to reach the goal. Obtaining a microcolony in which almost all the cells are in the follower state and only a few in the leader state seems to be the most difficult task. A small number of leader cells struggle to produce enough signal to turn the rest of the microcolony in the follower state. It is possible to obtain a microcolony in which the majority of cells are followers by increasing as much as possible the production of signal. Reaching the goal of a microcolony that is split in half between leaders and followers is comparatively easy. The best strategy seems to be increasing slightly the production of the enzyme. To end up with a majority of leaders, instead, it is advisable to increase the basal expression of the coin flipper module. At the end of the chapter, a possible future application of the leader election circuit, the spontaneous formation of spatial patterns in a microcolony, is modeled with the finite state machine formalism. The gro simulations provide insights into the genetic components that are needed to implement the behavior. In particular, since both the examples of pattern formation rely on a local version of Leader Election, a short-range communication system is essential. Moreover, new synthetic components that allow to reliably downregulate the growth rate in specific cells without side effects need to be developed. In the appendix are listed the gro code utilized to simulate the model of the circuit, a script in the Python programming language that was used to split the simulations on a Linux cluster and the Matlab code developed to analyze the data.

Development and characterization of micromachined devices for separation techniques

Nowadays microfluidic is becoming an important technology in many chemical and biological processes and analysis applications. The potential to replace large-scale conventional laboratory instrumentation with miniaturized and self-contained systems, (called lab-on-a-chip (LOC) or point-of-care-testing (POCT)), offers a variety of advantages such as low reagent consumption, faster analysis speeds, and the capability of operating in a massively parallel scale in order to achieve high-throughput. Micro-electro-mechanical-systems (MEMS) technologies enable both the fabrication of miniaturized system and the possibility of developing compact and portable systems. The work described in this dissertation is towards the development of micromachined separation devices for both high-speed gas chromatography (HSGC) and gravitational field-flow fractionation (GrFFF) using MEMS technologies. Concerning the HSGC, a complete platform of three MEMS-based GC core components (injector, separation column and detector) is designed, fabricated and characterized. The microinjector consists of a set of pneumatically driven microvalves, based on a polymeric actuating membrane. Experimental results demonstrate that the microinjector is able to guarantee low dead volumes, fast actuation time, a wide operating temperature range and high chemical inertness. The microcolumn consists of an all-silicon microcolumn having a nearly circular cross-section channel. The extensive characterization has produced separation performances very close to the theoretical ideal expectations. A thermal conductivity detector (TCD) is chosen as most proper detector to be miniaturized since the volume reduction of the detector chamber results in increased mass and reduced dead volumes. The microTDC shows a good sensitivity and a very wide dynamic range. Finally a feasibility study for miniaturizing a channel suited for GrFFF is performed. The proposed GrFFF microchannel is at early stage of development, but represents a first step for the realization of a highly portable and potentially low-cost POCT device for biomedical applications.

Solid-state NMR on columnar supramolecular structures

The present work deals with the characterisation of three columnar self-assembled systems, that is, benzene-1,3,5-tricarboxamides, a peripherally thioalkyl-substituted phthalocyanine, and several oligo-(p-phenylenevinylene)s. In order to probe the supramolecular organisation solid-state NMR has been used as the main technique, supported by X-ray measurements, theoretical methods, and thermal analysis. rnrnBenzene-1,3,5-tricarboxamides (BTAs) turned out to be well suited model compounds to study various fundamental supramolecular interactions, such as π-π-interactions, hydrogen bonding, as well as dynamic and steric effects of attached side chains. Six BTAs have been investigated in total, five with a CO-centred amide group bearing different side chains and one with an inverted N-centred amide group. The physical properties of these BTAs have been investigated as a function of temperature. The results indicated that in case of the CO-centred BTAs the stability of the columnar mesophase depends strongly on the nature of the side chains. Further experiments revealed a coplanar orientation of adjacent BTA molecules in the columnar assembly of CO-centred BTAs, whereas the N-centred BTA, showed a deviating not fully coplanar arrangement. These differences were ascribed to distinct hydrogen bonding schemes, involving a parallel alignment of hydrogen bonds in case of CO-centred BTAs and an antiparallel alignment in case of the N-centred counterpart.rnrn The fundamental insights of the supramolecular organisation of BTAs could be partially adapted to an octa-substituted phthalocyanine with thiododecyl moieties. Solid-state NMR in combination with chemical shift calculations determined a tilted herringbone arrangement of phthalocyanine rings in the crystalline phase as well as in the mesophase. Moreover, 1H NMR measurements in the mesophase of this compound suggested an axial rotation of molecules, which is inhibited in the crystalline phase.rnrnAs a third task, the supramolecular assembly of oligo-(p-phenylenevinylene)s of varying length and with different polar head groups have been investigated by a combined X-ray and solid-state NMR study. The results revealed a columnar structure formation of these compounds, being promoted by phase separation of alkyl side chains and aromatic rigid rods. In this system solid-state NMR yielded meaningful insight into the isotropisation process of butoxy and 2-S-methylbutoxy substituted oligo-(p-phenylenevinylene) rods.rn

Charge-transport simulations in organic semiconductors

In this thesis we have extended the methods for microscopic charge-transport simulations for organic semiconductors. In these materials the weak intermolecular interactions lead to spatially localized charge carriers, and the charge transport occurs as an activated hopping process between diabatic states. In addition to weak electronic couplings between these states, different electrostatic environments in the organic material lead to a broadening of the density of states for the charge energies which limits carrier mobilities.rnThe contributions to the method development includern(i) the derivation of a bimolecular charge-transfer rate,rn(ii) the efficient evaluation of intermolecular (outer-sphere) reorganization energies,rn(iii) the investigation of effects of conformational disorder on intramolecular reorganization energies or internal site energiesrnand (iv) the inclusion of self-consistent polarization interactions for calculation of charge energies.These methods were applied to study charge transport in amorphous phases of small molecules used in the emission layer of organic light emitting diodes (OLED).rnWhen bulky substituents are attached to an aromatic core in order to adjust energy levels or prevent crystallization, a small amount of delocalization of the frontier orbital to the substituents can increase electronic couplings between neighboring molecules. This leads to improved charge-transfer rates and, hence, larger charge-mobility. We therefore suggest using the mesomeric effect (as opposed to the inductive effect) when attaching substituents to aromatic cores, which is necessary for example in deep blue OLEDs, where the energy levels of a host molecule have to be adjusted to those of the emitter.rnFurthermore, the energy landscape for charges in an amorphous phase cannot be predicted by mesoscopic models because they approximate the realistic morphology by a lattice and represent molecular charge distributions in a multipole expansion. The microscopic approach shows that a polarization-induced stabilization of a molecule in its charged and neutral states can lead to large shifts, broadening, and traps in the distribution of charge energies. These results are especially important for multi-component systems (the emission layer of an OLED or the donor-acceptor interface of an organic solar cell), if the change in polarizability upon charging (or excitation in case of energy transport) is different for the components. Thus, the polarizability change upon charging or excitation should be added to the set of molecular parameters essential for understanding charge and energy transport in organic semiconductors.rnWe also studied charge transport in self-assembled systems, where intermolecular packing motives induced by side chains can increase electronic couplings between molecules. This leads to larger charge mobility, which is essential to improve devices such as organic field effect transistors, where low carrier mobilities limit the switching frequency.rnHowever, it is not sufficient to match the average local molecular order induced by the sidernchains (such as the pitch angle between consecutive molecules in a discotic mesophase) with maxima of the electronic couplings.rnIt is also important to make the corresponding distributions as narrow as possible compared to the window determined by the closest minima of thernelectronic couplings. This is especially important in one-dimensional systems, where charge transport is limited by the smallest electronic couplings.rnThe immediate implication for compound design is that the side chains should assist the self-assemblingrnprocess not only via soft entropic interactions, but also via stronger specific interactions, such as hydrogen bonding.rnrnrnrn

Functional dna nanostructures for in vitro biosensing in live cells

DNA is a fascinating biomolecule that is well known for its genetic role in living systems. The emerging area of DNA nanotechnology provides an alternative view that exploits unparallel self-assembly ability of DNA molecules for material use of DNA. Although many reports exist on the results of DNA self-assembling systems, still few of them focus on the in vitro study about the function of such DNA nanostructures in live cells. Due to this, there are still a limited research about the in vitro functionality of such designs. To address an aspect of this issue, we have designed, synthesized and characterized two multifunctional fluorescencent nanobiosensors by DNA self-assembling. Each structure was designed and implemented to be introduced in live cells in order to give information on their functioning in real-time. Computational tools were used in order to design a graphic model of two new DNA motifs and also to obtain the specific sequences to all the ssDNA molecules. By thermal self-assembly techniques we have successfully synthesized the structure and corroborate their formation by the PAGE technique. In addition, we have established the conditions to characterize their structural conformation change when they perform their sensor response. The sensing behavior was also accomplished by fluorescence spectroscopy techniques; FRET evaluation and fluorescence microscopy imaging. Providing the evidence about their adequate sensing performance outside and inside the cells detected in real-time. In a preliminary evaluation we have tried to show the in vitro functionality of our structures in different cancer cell lines with the ability to perform local sensing responses. Our findings suggest that DNA sensor nanostructures could serve as a platform to exploit further therapeutic achievements in live cells.

Model-Centric, Context-Aware Software Adaptation

Software must be constantly adapted to changing requirements. The time scale, abstraction level and granularity of adaptations may vary from short-term, fine-grained adaptation to long-term, coarse-grained evolution. Fine-grained, dynamic and context-dependent adaptations can be particularly difficult to realize in long-lived, large-scale software systems. We argue that, in order to effectively and efficiently deploy such changes, adaptive applications must be built on an infrastructure that is not just model-driven, but is both model-centric and context-aware. Specifically, this means that high-level, causally-connected models of the application and the software infrastructure itself should be available at run-time, and that changes may need to be scoped to the run-time execution context. We first review the dimensions of software adaptation and evolution, and then we show how model-centric design can address the adaptation needs of a variety of applications that span these dimensions. We demonstrate through concrete examples how model-centric and context-aware designs work at the level of application interface, programming language and runtime. We then propose a research agenda for a model-centric development environment that supports dynamic software adaptation and evolution.

Back to the future in one week - implementing a Smalltalk VM in PyPy

We report on our experiences with the Spy project, including implementation details and benchmark results. Spy is a re-implementation of the Squeak (i.e., Smalltalk-80) VM using the PyPy toolchain. The PyPy project allows code written in RPython, a subset of Python, to be translated to a multitude of different backends and architectures. During the translation, many aspects of the implementation can be independently tuned, such as the garbage collection algorithm or threading implementation. In this way, a whole host of interpreters can be derived from one abstract interpreter definition. Spy aims to bring these benefits to Squeak, allowing for greater portability and, eventually, improved performance. The current Spy codebase is able to run a small set of benchmarks that demonstrate performance superior to many similar Smalltalk VMs, but which still run slower than in Squeak itself. Spy was built from scratch over the course of a week during a joint Squeak-PyPy Sprint in Bern last autumn.

A discourse-theoretic approach to negotiated rulemaking

In 1996 and in 1997, Congress ordered the Secretary of Health and Human Services to undertake a process of negotiated rulemaking, which is authorized under the Negotiated Rulemaking Act of 1990, on three separate rulemaking matters. Other Federal agencies, including the Environmental Protection Agency and the Occupational Health and Safety Administration, have also made use of this procedure. As part of the program to reinvent government, President Clinton has issued an executive order requiring federal agencies to engage in some negotiated rulemaking procedures. I present an analytic, interpretative and critical approach to looking at the statutory and regulatory provisions for negotiated rulemaking as related to issues of democratic governance surrounding the problem of delegation of legislative power. The paradigm of law delineated by Jürgen Habermas, which sets law the task of achieving social or value integration as well as integration of systems, provides the background theory for a critique of such processes. My research questions are two. First, why should a citizen obey a regulation which is the result of negotiation by directly interested parties? Second, what is the potential effect of negotiated rulemaking on other institutions for deliberative democracy? For the internal critique I argue that the procedures for negotiated rulemaking will not produce among the participants the agreement and cooperation which is the legislative intent. For the external critique I argue that negotiated rulemaking will not result in democratically-legitimated regulation. In addition, the practice of negotiated rulemaking will further weaken the functioning of the public sphere, as Habermas theorizes it, as the central institution of deliberative democracy. The primary implication is the need to mitigate further development of administrative agencies as isolated, self-regulating systems, which have been loosened from the controls of democratic governance, through the development of a robust public sphere in which affected persons may achieve mutual understanding. ^

Ser un trabajador estatal : Sentidos del trabajo, moralidades y acción colectiva de trabajadores de la salud pública

Los sistemas de auto-clasificación que enuncian los trabajadores del Hospital Castro Rendón de Neuquén son múltiples y se ponen en juego en diversos contextos, operando como categorías con las que se definen a sí mismos y a los otros. A partir de una estrategia metodológica cualitativa basada en la realización de observaciones participantes y entrevistas en profundidad, en este artículo se analiza cómo se pone en juego la categoría de 'trabajador estatal' en tanto forma de auto-adscripción en el trabajo cotidiano y durante los momentos de huelga. Los sentidos asociados al trabajo son centrales para comprender la lógica de acción de los actores, ya que sirven de sustento de una comunidad moral y profesional de trabajadores que se opone a los 'funcionarios' dentro de las estructuras del Estado provincial. A su vez ello permite mostrar la lógica en que se manifiestan las disputas en los procesos de gestión de las políticas de salud pública neuquina.

Ser un trabajador estatal : Sentidos del trabajo, moralidades y acción colectiva de trabajadores de la salud pública

Los sistemas de auto-clasificación que enuncian los trabajadores del Hospital Castro Rendón de Neuquén son múltiples y se ponen en juego en diversos contextos, operando como categorías con las que se definen a sí mismos y a los otros. A partir de una estrategia metodológica cualitativa basada en la realización de observaciones participantes y entrevistas en profundidad, en este artículo se analiza cómo se pone en juego la categoría de 'trabajador estatal' en tanto forma de auto-adscripción en el trabajo cotidiano y durante los momentos de huelga. Los sentidos asociados al trabajo son centrales para comprender la lógica de acción de los actores, ya que sirven de sustento de una comunidad moral y profesional de trabajadores que se opone a los 'funcionarios' dentro de las estructuras del Estado provincial. A su vez ello permite mostrar la lógica en que se manifiestan las disputas en los procesos de gestión de las políticas de salud pública neuquina.

Ser un trabajador estatal : Sentidos del trabajo, moralidades y acción colectiva de trabajadores de la salud pública

Los sistemas de auto-clasificación que enuncian los trabajadores del Hospital Castro Rendón de Neuquén son múltiples y se ponen en juego en diversos contextos, operando como categorías con las que se definen a sí mismos y a los otros. A partir de una estrategia metodológica cualitativa basada en la realización de observaciones participantes y entrevistas en profundidad, en este artículo se analiza cómo se pone en juego la categoría de 'trabajador estatal' en tanto forma de auto-adscripción en el trabajo cotidiano y durante los momentos de huelga. Los sentidos asociados al trabajo son centrales para comprender la lógica de acción de los actores, ya que sirven de sustento de una comunidad moral y profesional de trabajadores que se opone a los 'funcionarios' dentro de las estructuras del Estado provincial. A su vez ello permite mostrar la lógica en que se manifiestan las disputas en los procesos de gestión de las políticas de salud pública neuquina.

Ser un trabajador estatal : Sentidos del trabajo, moralidades y acción colectiva de trabajadores de la salud pública

Los sistemas de auto-clasificación que enuncian los trabajadores del Hospital Castro Rendón de Neuquén son múltiples y se ponen en juego en diversos contextos, operando como categorías con las que se definen a sí mismos y a los otros. A partir de una estrategia metodológica cualitativa basada en la realización de observaciones participantes y entrevistas en profundidad, en este artículo se analiza cómo se pone en juego la categoría de 'trabajador estatal' en tanto forma de auto-adscripción en el trabajo cotidiano y durante los momentos de huelga. Los sentidos asociados al trabajo son centrales para comprender la lógica de acción de los actores, ya que sirven de sustento de una comunidad moral y profesional de trabajadores que se opone a los 'funcionarios' dentro de las estructuras del Estado provincial. A su vez ello permite mostrar la lógica en que se manifiestan las disputas en los procesos de gestión de las políticas de salud pública neuquina.

Modelado de materiales piezoeléctricos para aplicaciones de autoalimentación en entornos viales

Este proyecto continua con el estudio iniciado en los proyectos: Alimentación “Energy Harvesting” basada en fuentes piezoeléctricas, Alimentación autónoma: aplicación a fuente piezoeléctrica y Banco de pruebas para sistemas autoalimentados en aplicaciones viales, que se realizaron anteriormente. Este estudio se basa en la búsqueda de soluciones de alimentación Energy Harvesting centrados en fuentes piezoeléctricas. El objetivo de este estudio es conocer las posibilidades que pueden ofrecer los materiales piezoeléctricos para alimentación autónoma cuando son excitados por vehículos en diferentes circunstancias y entornos viales. Para la realización de este estudio se han utilizado señales provenientes del banco de ensayos, así como señales obtenidas de una instalación construida en un vial del Campus. Para poder realizar el estudio de los diversos materiales piezoeléctricos utilizados en este proyecto, se necesitan conocer las características de los modelos eléctricos. Para obtener estas características se ha diseñado un programa basado en LabView, este programa además puede modificar la señal para que simule las diversas circunstancias a las que pueden estar sometidos los diferentes materiales piezoeléctricos. En este estudio se ha tenido en cuenta la distancia de seguridad entre vehículos para diferentes velocidades y la posibilidad de poder amplificar la excitación que pueden recibir los diversos materiales. Utilizando el programa PSpice OrCAD® se realizan los diferentes modelos con el objetivo de observar el comportamiento de los materiales bajo diversas circunstancias. También se han utilizado varias topologías rectificadoras diferentes para poder comprobar en que situación se puede obtener la máxima tensión acumulada posible. Además también se ha evaluado la máxima potencia que puede entregar cada material en cada situación. Por ultimo se han realizado varias pruebas prácticas con el banco de ensayos para comprobar la acumulación energética real que se puede obtener de los materiales instalados en él. También se ha realizado el estudio de una aplicación práctica que sea capaz de alimentar pequeños circuitos o sensores de poco consumo. Abstract This Project goes on with the study started in the projects Feeding “Energy Harvesting” based on piezoelectric sources, independent feeding: application to piezoelectric source and testing bench to self fed systems in roads applications that were previously done. This study is based on the search of feeding solutions Energy Harvesting focus on piezoelectric sources. The aim of this study is know the different piezoelectric materials possibilities that can offer to independent feeding when different circumstances and road surroundings are excited by vehicles in. To develop this study several signals of the testing bench have been used and also signals get from an installation constructed on a Campus road. As far as the study of the different piezoelectric materials used in this project is concerned we should know the electrical models features. In order to obtain these characteristics a program based on LabView was designed, this program can modify the signal so that it simulates the diverse circumstances to which they can be put under the different piezoelectric materials. In this study I have bearded in mind the safe distance between vehicles for different speeds and the possibility of being able to amplify the excitation that can receive the diverse materials. Using the program PSpice OrCAD® the different models with the objective are made to observe the behaviour of the materials under diverse circumstances. Also several different rectifying topologies have been used to be able to verify the maximum overvoltage accumulated. In addition I have assessed the maximum power that can give each material in each situation. Last but not least different practical proofs with the testing bench have been done to check the actual energy accumulation that can be obtained from the materials installed on it. Also the study of a practical application has been made that is able to feed small circuits or low consumption sensor.