In recent years, there has been increasing interest in the advancement of microrobotic systems in micro-engineering, micro-fabrication, biological research and biomedical applications. Untethered magnetic-based microrobotic systems are one of the most widely developing groups of microrobotic systems that have been extensively explored for biological and biomedical micro-manipulations. These systems show promise in resolving problems related to on-board power supply limitations as well as mechanical contact sealing and lubrication. In this thesis, a high precision magnetic untethered microrobotic system is demonstrated for micro-handling tasks. A key aspect of the proposed platform concerns the integration of magnetic levitation technology and bilateral macro-micro teleoperation for human intervention to avoid imperceptible failures in poorly observed micro-domain environments. The developed platform has three basic subsystems: a magnetic untethered microrobotic system (MUMS), a haptic device, and a scaled bilateral teleoperation system. The MUMS produces and regulates a magnetic field for non-contact propelling of a microrobot. In order to achieve a controlled motion of the magnetically levitated microrobot, a mathematical force model of the magnetic propulsion mechanism is developed and used to design various control systems. In the workspace of 30 ?? 32 ?? 32 mm ³, both PID and LQG\LTR controllers perform similarly the position accuracy of 10 ?? m in a vertical direction and 2 ?? m in a horizontal motion. The MUMS is equipped with an eddy-current damper to enhance its inherent damping factor in the microrobot's horizontal motions. This paper deals with the modeling and analysis of an eddy-current damper that is formed by a conductive plate placed below the levitated microrobot to overcome inherent dynamical vibrations and improve motion precision. The modeling of eddy-current distribution in the conductive plate is investigated by solving the diffusion equation for vector magnetic potential, and an analytical expression for the horizontal damping force is presented and experimentally validated. It is demonstrated that eddy-current damping is a crucial technique for increasing the damping coefficient in a non-contact way and for improving levitation performance. The damping can be widely used in applications of magnetic actuation systems in micro-manipulation and micro-fabrication. To determine the position of the microrobot in a workspace, the MUMS uses high-accuracy laser sensors. However, laser positioning techniques can only be used in highly transparent environments. A novel technique based on real-time magnetic flux measurement has been proposed for the position estimation of the microrobot in case of laser beam blockage, whereby a combination of Hall-effect sensors is employed to find the microrobot's position in free motion by using the produced magnetic flux. In free motion, the microrobot tends to move toward the horizontally zero magnetic field gradient, B_max location. As another key feature of the magnetic flux measurement, it was realized that the applied force from the environment to the microrobot can be estimated as linearly proportional to the distance of the microrobot from the B_max location. The developed micro-domain force estimation method is verified experimentally with an accuracy of 1.27 ?? N. A bilateral macro-micro teleoperation technique is employed in the MUMS for the telepresence of a human operator in the task environment. A gain-switching position-position teleoperation scheme is employed and a human operator controls the motion of the microrobot via a master manipulator for dexterous micro-manipulation tasks. The operator can sense a strong force during micro-domain tasks if the microrobot encounters a stiff environment, and the effect of hard contact is fed back to the operator's hand. The position-position method works for both free motion and hard contact. However, to enhance the feeling of a micro-domain environment in the human operator, the scaled force must be transferred to a human, thereby realizing a direct-force-reflection bilateral teleoperation. Additionally, a human-assisted virtual reality interface is developed to improve a human operator's skills in using the haptic-enabled platform, before carrying out an actual dexterous task.

Magnetic micro-robots are small robots under 1mm in size, made of magnetic materials, with relatively simple structures and functionalities. Such micro-robots can be actuated and controlled remotely by externally applied magnetic fields, and hence have the potential to access small and enclosed spaces. Most of the existing magnetic micro-robots can operate in wet environments. When the robots are actuated by the applied magnetic field to move inside a viscous liquid, they invoke flow motions around them inside the liquid. The induced flows are relatively local as the velocity of these flows decays rapidly with the distance from a moving robot, and the flow patterns are highly correlated with the motions of the micro-robots which are controllable by the applied magnetic field. Therefore, it is possible to generate local flow patterns that cannot be easily done using other microfluidic techniques. In this work we propose to use rotational motion of the magnetic micro-robots for local manipulation of flows. We employ electromagnetic techniques to successfully deliver actuation and motion control onto the micro-robots. Rotational magnetic field is applied to induce rotational motion of micro-robots both when they stay near a surface and are suspended in the liquid. Rotational flows are locally generated in the vicinity of micro-robots inside the viscous liquid. Implementation of three major applications using the flows generated by the rotating micro-robots are demonstrated in this work: 1) Two-dimensional (2D) non-contact manipulation of micro-objects. 2) Three-dimensional (3D) propulsion for the micro-robot to swim in a liquid. 3) Size-based sorting of micro-particles in microfluidic channels under continuous flow. The first two applications occur in otherwise quiescent liquid, while the third requires the presence of non-zero background flow. For the first application, we propose two methods to achieve precise positioning of the microrobots on a surface: 1) Using visual-feedback-control to adjust the rotation for one single microrobot. Micro-robot can be precisely positioned at any location on a surface using this method. 2) Using a specially prepared surface with magnetic micro-docks embedded in it, which act as local magnetic traps for multiple micro-robots to hold their positions and operate in parallel. Physical models are established for both the micro-robot and the micro-objects present in the induced rotational flow. The rotational flows induced by rotating micro-robots are studied with numerical simulations. Experimental demonstrations are first given at sub-millimeter scale to verify the proposed method. Micro-manipulation of polymer beads is performed with both positioncontrol methods. Automated micro-manipulation is also achieved using visual-feedback. Micromanipulation at micron-scale is then performed to demonstrate the scalability and versatility of the proposed method. Non-contact manipulation is achieved for various micro-objects, including biological samples, using a single spherical micro-robot. Inspired by flagellated microorganisms in nature, we explore the hydrodynamics of an elastic rod-like structure - the artificial flagellum, and verify by both simulation and experiments that rotation and deformation of such structure can result in a propulsive force on a micro-robot it is attached to. Optimization of flagellum geometry is achieved for a single flagellum. A swimming micro-robot design with multiple flexible flagella is proposed and fabricated via an inexpensive micro-fabrication process involving photolithography, micro-molding and manual assembly. Experiments are perform to characterize the propulsive force generation and the resulting swimming performance of the fabricated micro-robots. It is demonstrated that the swimming speed can be improved by increasing the number of attached flagella. For the size-based sorting application, we integrate the micro-robots into microfluidic channels by using the substrate embedded with magnetic micro-docks, which are capable of holding the robots under continuous flow inside the channels while the robots spin. Numerical analysis is carried out of the flows inside the microfluidic channel in the presence of rotating micro-robots, and a physical model is established and discussed for size-based lateral migration of spherical micro-objects inside the induced rotational flows. Experimental demonstrations are performed for using the induced rotational flows to divert the trajectories of micro-particles based on their sizes under continuous flow. In addition, we propose the method of using the two photon polymerization (TPP) technique to fabricate magnetic micro-robots with complex shapes. The method could also achieve fabrication of arrays of micro-robots for more sophisticated applications. However, experimental results prove that the TPP is insufficient to achieve magnetic micro-robots that meet our needs for size-based sorting application due to physical limitations of the materials. Despite that, it is potentially powerful and suitable for fabrication of micro-robots with complex structures at small scales.

<p>Microrobots have a promising prospect to be used in healthcare and bioengineering applications due to their capability to gently access small and delicate body sites. Unfortunately, traditional materials used for the fabrication of microrobots are rigid, hindering safe operation due to the transfer of high stresses to the surrounding tissue. Additionally, traditional microrobots are often not biocompatible, which threatens the health of the patient if not properly retrieved. This dissertation describes the fabrication and actuation of small-scale (several micrometers in all dimensions) magnetic robots that are soft, biocompatible, and capable of moving over smooth and corrugated surface. <u>S</u>oft <u>M</u>agnetic <u>M</u>icro <u>R</u>obots (SMµRs) can carry payloads in their porous interior and release them using external magnetic inputs. SMµRs has therefore the potential to be used in a wide range of applications—including targeted drug release and remote biosensing and bio sampling—and access a number of difficult-to-reach sites in the human body, such as intestines or blood vessels. The structure of SMµRs consist of three thin layers: Two layers of polymer with embedded magnetic particles aligned along a preferential direction. One porous layer, in between the magnetic layers, where the SMµRs can accumulate and release payloads. SMµRs are small, light in weight, and fast and inexpensive to fabricate. Moreover, the manufacturing of SMµRs is compatible with large-scale production processes, facilitating their future commercial exploitation. Using external rotating magnetic fields, the position of the SMµRs can be controlled wirelessly <i>via</i> tumbling locomotion. We demonstrate two types of tumbling locomotion (length-wise and side-wise) as well as the possibility to release the internal payload of the SMµRs in a discrete or continuous manner using only changes in the intensity of the external magnetic field. We studied the performance of SMµRs under a variety of environmental conditions as well as their capability of overcoming obstacles.</p>

Nanomaterials have been widely investigated for improving the treatment of diseases acting as vectors for diverse therapies and as diagnostic tools. Iron-based nanowires possess promising potential for biomedical applications due to their outstanding properties. The combination of different therapeutic and diagnostic strategies into one single platform is an approach for more efficient and safer treatments. In this thesis, I investigate the application of iron-iron oxide core-shell nanowires as therapeutic agents for cancer treatment. In particular, a novel method for multimodal cancer cell destruction was developed combining the optical, magneto-mechanical and chemotherapeutic properties of functionalized nanowires. By functionalizing the nanowires with doxorubicin through a pH-sensitive linker, the first treatment modality was achieved by selective intracellular drug release. The second treatment modality utilizes the mechanical disturbance exerted by the nanowires upon the application of a low-power alternating magnetic field. The third treatment modality exploits the capability of the nanowires to transform optical energy, absorbed from near-infrared irradiation, into heat. The efficiency of the three treatment modalities both independently and combined were tested in breast cancer cells with near complete cell death (90%). The combination of the different strategies can potentially reduce side effects and treatment time. Additionally, I studied the potential of these iron-iron oxide core-shell nanowires as diagnostic tools, included in the Appendix of this dissertation. Specifically, I studied their capability to act as magnetic resonance imaging contrast agents for cell labeling, detection and tracking. Therein, a high performance as T2 contrast agents was confirmed evaluating the effect of oxidation and surface coatings on the T2 contrast in the tailored transverse relaxivities. The detection of nanowire-labeled cancer cells was demonstrated in T2-weighted images of cells implanted in tissue-mimicking phantoms and in mouse brain. Labeling the cells with nanowires enabled high-resolution cell detection after in vivo implantation (~10 cells) over a minimum of 40 days. The capability of these magnetic nanowires of being remotely controllable and detectable make them an attractive option in the treatment and diagnosis of cancer and in cell therapy. Future directions include preclinical studies for testing the nanowire-based photothermal therapy for tumor ablation.

The mobility and biomedical applications of a microscale magnetic tumbling (μTUM) robot capable of traversing complex terrains in dry and wet environments is explored. Roughly 800 x 400 x 100 μm in size, the robot is fabricated using standard photolithography techniques and consists of a rectangular polymeric body with embedded NdFeB particles. Static force analysis and dynamic modeling of its motion characteristics are performed with experimental verification. Techniques for simulating the intermittent, non-contact behavior of tumbling locomotion are used to find an optimized design for the microrobot, reducing time and resources spent on physical fabrication. When subject to a magnetic field as low as 3 mT, the microrobot is able to translate at speeds of over 30 body lengths/s (24 mm/s) in dry conditions and up to 8 body lengths/s (6.8 mm/s) in wet conditions. It can climb inclined planes up to 60° in wet conditions and up to 45° in dry conditions. Maximum open loop straight-line trajectory errors of less than 4% and 2% of the traversal distance in the vertical and horizontal directions, respectively, were also observed. Full two-dimensional directional control of the microrobot was shown through the traversal of a P-shaped trajectory. The microrobot's real-time position can be accurately tracked through visual occlusions using ultrasound imaging. When applied as a coating, a fluorescein payload was found to diffuse over a two hour time period from the microrobot. Cytotoxicity tests also demonstrated that the microrobot's SU-8 body is biocompatible with murine fibroblasts. The microrobot's capabilities make it promising for targeted drug delivery and other in vivo biomedical applications.

Les systèmes d’actionnement à distance pour la manipulation d’objets de taille micrométrique ont connu un développement sans précédent ces dernières années dans les laboratoires de recherche. Ils permettent de contrôler à distance le déplacement et l’orientation d’objets en appliquant des champs de force à distance. Ils sont donc spécialement adaptés pour agir dans des milieux confinés pour lesquels les problèmes d’accessibilité empêchent l’utilisation de manipulateurs robotisés classiques. De plus la faible inertie de ces systèmes permet d’atteindre des cadences de manipulation importantes. Parmi les effets physiques exploitables pour actionner ces systèmes une attention particulière est portée sur les effets magnétiques, en raison des niveaux de forces élevés atteignables. L’état de l’art montre un nombre de travaux importants dans le domaine de l’actionnement magnétique en environnement liquide. Cependant les vitesses atteignables sont limitées par les frottements visqueux. Quelques études font état de l’utilisation de l’actionnement magnétique en milieu ambiant, mais les forces d’adhésion entre le substrat et la particule rend le système peu répétable. Cette thèse propose une approche originale alliant faibles frottements visqueux et grande répétabilité en considérant un milieu de travail peu étudié : l’interface air/liquide. Cette thèse s’intéresse plus particulièrement à la modélisation, la caractérisation, l’analyse des performances et la commande d’un système d’actionnement magnétique à l’interface air/liquide pour des applications à l’échelle micrométrique. / In recent years research laboratories have shown an increasing interest for non-contact actuation systems at micrometer scale. These systems control both the displacement and the orientation of the objects using remote force fields. They are of major interest in confined spaces in which traditional approaches based on robotic grippers are not suitable. In addition high manipulation throughputs can be reached due to the low inertia of these systems. Several physical principles can be considered as the actuation source. Among them a special attention is given to magnetic forces due to the high forces that can be applied to the objects. A large amount of work has been carried out on magnetic actuation systems for manipulation in liquid environments. However velocities are limited by viscous effects. A few studies are reported on magnetic systems in ambient environments. However repeatability is decreased by adhesion forces between the substrate and the objects. This work proposes an original approach with a good trade off between low viscous effects and high repeatability based on the use of a specific environment: the air/liquid interface. This thesis presents the modelling, the characterization, the performance analysis and the control of a magnetic actuation system at the air/liquid interface for applications at the micrometer scale.

This dissertation develops a general framework for designing stabilizing feedback controllers and observers for dynamics with state/time dependent gains on the control signals and measured outputs. These gains have potential singularity periods but satisfy a technically non-trivial condition referred to as persistence of excitation. A persistence filter design constitutes the primary theoretical innovation of this work around which the controller and observer development is centered. Application areas of singular gain systems considered in this study include robotics, biomechanics, intelligent structures and spacecrafts. Several representative problems involving singular, time-dependent gains are addressed. The specific contributions of this dissertation are outlined as follows: (i) a stabilizing feedback for linear, single-input systems with time-varying, singular control scaling is designed that allows arbitrary exponential convergence rate for the closed-loop dynamics. An adaptive control generalization of this result allows asymptotic convergence in presence of unknown plant parameters. An extension to a special, single-input nonlinear system in the controller canonical form is also proposed. It is proven that this control design results in bounded tracking error signals for a trajectory tracking objective; (ii) observer design for linear, single-output systems with time-varying, singular measurement gains is considered. A persistence filter similar in structure to the control counterpart aids an observer design that guarantees exponential state reconstruction with arbitrary convergence rates; (iii) the observer and controller designs are combined to obtain an exponentially stabilizing output feedback controller for linear, single-input, single-output dynamics with singular gains on both the control and measurements. A novel separation property is established as a consequence. The construction motivates applications to stabilization with reversible transducers which can switch between sensor and actuator modes. The results are verified on two illustrative applications, vibration control using piezoelectric devices and inverted pendulum stabilization with a DC motor. The linear result is further generalized to include state dependent gains; (iv) application of the persistence filter theory to spacecraft attitude stabilization using intermittent actuation is explored. The intermittence is characterized by a time-varying, periodically singular control gain. A nonlinear persistence filter allows construction of an exponentially stabilizing controller and simulations verify convergence with intermittent actuation where conventional proportional-derivative control fails; (v) a stabilization result for a special multi-input, linear system with time-varying matrix control gains is presented. The matrix gain is assumed to be diagonal but allows fewer controls than states subject to a controllability assumption in absence of the singular gain matrix. The single-input adaptive control results are shown to extend to the multi-input case. An application to angular velocity stabilization of an underactuated rigid spacecraft is considered. / text

Orientador: Prof. Dr. José Antonio Souza / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, Santo André, 2018. / O objetivo deste trabalho e sintetizar materiais magneticos e semicondutores ocos micro/nanoestruturados hierarquicamente, para obter um melhor entendimento das propriedades fisicas e explorar aplicacoes tecnologicas. Inicialmente, microtubos de hematita e magnetita foram sintetizados por oxidacao termica juntamente com uma corrente eletrica aplicada e utilizando-se o microfio de ferro metalico como precursor. A fraccao volumetrica de Fe2O3(hematite) e Fe3O4(magnetite) nos microtubos e a formacao das nanoestruturas de hematite na superficie pode ser controlada por alteracoes sistematicas dos parametros de sintese tais como temperatura, rampa de aquecimento, tempo de aquecimento e valor da corrente electrica. A reacao quimica de oxidacao envolve um processo onde uma fina camada de oxido e formada primeiro na superficie do metal, seguida por difusao simultanea de ions metalicos atraves da camada oxida e difusao de oxigenio da atmosfera para o interior. A difusao para fora e mais rapida, levando a criacao de vacancias que coalescem em poros formando os microtubos. Medidas de resistividade eletrica in situ foram realizadas durante o processo de oxidacao mostrando todo o processo de formacao do microtubo. Imagens de microscopia eletronica de varredura mostram a morfologia do microtubo com diametro variando de 40 ¿Êm a 100 ¿Êm e comprimento de 5 mm. Medidas de difracao de raios-X em po evidenciam a presenca de fases cristalinas de hematita (Fe2O3) e magnetita (Fe3O4) nos microtubos. Nanoestruturas de hematita aparecem em forma de bastoes e fios dispersos homogeneamente ao redor da superficie do microtubo com diametros de 80-300 nm e comprimento de 1-5 ¿Êm. Experimentos in vitro envolvendo aderencia, migracao e proliferacao de culturas de celulas de fibroblastos na superficie dos microtubos indicaram a ausencia de citotoxicidade para este material. Tambem o calculo do torque e da forca magnetica desses microtubos com nanofios em funcao do gradiente de campo magnetico externo, mostrou que ele e robusto, abrindo a possibilidade para fabricacao de bio-microrobos magneticos para aplicacao em biotecnologia. Por outro lado, microarquiteturas ocas de SnS e ZnS decoradas com nanoestruturas foram sintetizadas por evaporacao termica livre de catalisadores utilizando microfios de metal e po de enxofre como materiais de partida. Para o SnS, observamos formacao de uma estrutura oca composta por uma camada metalica de Sn na superficie interna, e uma camada de SnS de estrutura ortorrombica com nanoestruturas de SnS na superficie. Para o ZnS, descobrimos a formacao de uma esfera oca com uma camada metalica na parte interna, uma camada de ZnS com fase cubica, e sobre ela nanoestruturas de ZnS com fase cristalina hexagonal cresceram homogeneamente. O diametro da microsfera e de 415 ¿Êm e os nanofios tem um diametro e comprimento medio de 70 nm e 7 ¿Êm, respectivamente. As microestruturas ocas semicondutoras de ZnS e SnS exibiram atividade eficiente para degradar azul de metileno sob irradiao com luz solar simulada. Os resultados revelam que essas nano/microestruturas possuem alta fotoatividade para degradacao organica. / The aim of this work is to synthesize hierarchically micro/nanostructured hollow magnetic and semiconductor materials, to obtain a better understanding on the physical properties, and find technological applications. Initially, hematite and magnetite microtubes were synthesized by thermal oxidation process along with the presence of an applied electrical current and using metallic iron microwire as a precursor. The volume fraction of both Fe2O3 (hematite) and Fe3O4 (magnetite) phase on microtubes can be controlled as well as surface nanostructures formation of hematite by systematic change of the synthesis parameters such as temperature, heating rate, annealing time and electrical current value. The oxidation chemical reaction involves a process where a thin oxide layer is formed first on the metal surface, followed by simultaneous outward diffusion of metal ions through the oxide scale and inward diffusion of oxygen from the atmosphere into the core. In our case, the outward diffusion is faster leading to the creation of vacancies which coalesce into voids forming the microtubes. In situ electrical resistivity measurements were carried out during the oxidation process showing the whole process of the microtube formation. Scanning electron microscopy images show microtube morphology with diameter ranging from 40 ìm to 100 ìm and length of 5 mm. X-ray powder diffraction measurements evidence the presence of hematite (Fe2O3) and magnetite (Fe3O4) crystal phases comprising microtubes. Nanostructures of hematite appear in form of sticks and wires homogeneously dispersed on the microtube surface with diameters ranking from 80 nm to 300 nm and length of 1 to 5 ìm. In vitro experiments involving adherence, migration, and proliferation of fibroblasts cell culture on the surface of the microtubes indicated the absence of immediate cytotoxicity for this material. We have also calculated both torque and driving magnetic force for these microtubes with nanowires as a function of external magnetic field gradient which were found to be robust opening the possibility for magnetic bio micro-robot device fabrication and application in biotechnology. On the other hand, SnS and ZnS hollow microarchitectures decorated with nanostructures were synthesized by catalysis free thermal evaporation technique using metal microwires and sulfur powder as starting materials. For SnS, we observed a hollow formation comprised of a thin metallic Sn layer in the inner surface, SnS orthorhombic structure thick layer with SnS nanostructures on the top. For ZnS, we found out the formation of hollow sphere with a thin metallic layer in the inner part, a thick cubic phase layer of ZnS, and on this second phase, nanostructures of ZnS hexagonal crystal phase grew up homogeneously. The microsphere diameter is about 415 ìm and the nanowires on the surface have average diameter of 70 nm and length 7 ìm. ZnS and SnS hollow semiconducting microstructures have exhibited efficient activity to degrade the methylene blue under simulated sunlight irradiation. The results reveal that these nano/microstructures have high photoactivity to organic degradation.

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Systems of interacting colloidal particles are ideal tools for studies of pattern formation and collective non-equilibrium dynamics on the mesoscopic scale. These processes are governed by the interaction between the particles, which can be tuned by sophisticated fabrication. In this thesis, self-assembly of artificially designed magnetic spheres dispersed in water has been studied via video microscopy. The particles are based on silica microspheres with hemispherical ferromagnetic coating of [Co/Pd] multilayers with perpendicular magnetic anisotropy. These particles are exceptional in that they exhibit an off-centered net magnetic moment and yet obey rotational and mirror symmetry. It has been demonstrated how these magnetic properties provide innovative flexibility in pattern formation and collective dynamics based on magnetostatic interactions on the mesoscopic scale. The results are supported by analytical and numerical calculations of interacting spheres with radially shifted point dipoles (sd-particles). In two dimensions, the particles spontaneously self-assemble into branched structures as a result of a bistable assembly behavior where neighboring particles exhibit a non-collinear magnetic orientation. It has been shown that these features, which are atypical for homogeneous systems of magnetic particles, can be reproduced by simulation. It employs a theoretical model of a sphere that contains a distribution of three radially shifted point dipoles in analogy to the magnetization distribution in the coated particles. The stability of the assembly has been examined further by external manipulation using optical tweezers and homogeneous magnetic fields. A rich variety of stable structures with diverse spatial and magnetic ordering has been found. Particularly, the collective alignment of the specially designed particles in external fields opens completely new possibilities for the remote control over reversible pattern formation on the micrometer scale. In time-dependent fields, the collective dynamics of the anisotropic particles has revealed a novel approach for magnetically actuated translation. The variety of stable structures particularly enables control over this motion. / Kolloidale Suspensionen sind geeignete Systeme zur Untersuchung von Strukturbildung und kollektiver Nichtgleichgewichtsdynamik in mesoskopischen Größenskalen. Diese Vorgänge werden durch die Wechselwirkung zwischen den Teilchen bestimmt, welche durch geeignete Partikelherstellung angepasst werden kann. In der vorliegenden Arbeit wird ein System von künstlich hergestellten magnetischen Partikelsuspensionen mittels Videomikroskopie untersucht. Quarzglas-Mikrokugeln wurden halbseitig mit einer ferromagnetischen Dünnschicht aus [Co/Pd] Multilagen mit senkrechter Anisotropie beschichtet. Solche Partikel sind ausgezeichnet durch ein resultierendes magnetisches Moment mit Rotations- und Spiegelsymmterie, welches zusätzlich vom Mittelpunkt der Kugel verschoben ist. Die vorliegende Arbeit zeigt, dass diese Besonderheit zu einer bisher unbekannten Flexibilität bei der mesoskopischen Strukturbildung und der kollektiven Dynamik auf der Basis magnetostatischer Wechselwirkung führt. Die vorgestellten Ergebnisse werden durch analytische und numerische Berechnungen unterstützt, denen ein Modell einer idealen Kugel mit verschobenem Dipol zugrunde liegt. Die zweidimensionale Selbstanordnung der Partikel zeigt experimentell zwei stabile Formen der Verknüpfung, welche zu verzweigten Strukturen mit unterschiedlich magnetischer Ausrichtung benachbarter Partikel führen. Diese für ein homogenenes System magnetischer Partikel außergewöhnlichen Eigenschaften konnten in Simulationen durch ein Modellsystem aus Kugeln mit drei verschobenen Punktdipolen reproduziert werden. Darüber hinaus wurde die spontante Anordnung unter externer Manipulation mittels optischer Pinzette und magnetischen Feldern untersucht. Es konnte eine Vielfalt an stabilen Strukturen mit verschiedenen magnetischen und strukturellen Anordnungen gefunden werden. Insbesondere die kollektive Ausrichtung dieser Partikel in externen Feldern eröffnet neuartige Möglichkeiten, kontrolliert und reversibel Mikrostrukturen zu erzeugen. In zeitabhängigen Feldern zeigen die anisotropen Partikel zusätzlich eine kollektive Dynamik welche eine neue Möglichkeit zum magnetischen Antrieb von Partikelagglomeraten eröffnet. Die Vielfalt der möglichen stabilen Strukturen erlaubt es in besonderer Weise diese Bewegung zu steuern.