16 research outputs found
Mechano-activated self-immolation of hydrogels via signal amplification
No full textCellular organisms possess intricate mechano-adaptive systems that enable them to sense forces and process them with (bio)chemical circuits for functional adaptation. Inspired by such processes, this study introduces a hydrogel system capable of mechanically activated and chemically transduced self-destruction. Our judiciously designed hydrogels can mechanically generate radicals that are processed and amplified in a self-propagating radical de-crosslinking reaction, ultimately leading to mechanically triggered self-immolation. We put such systems to work in mechano-induced debonding, and in a bilayer actuator, where swelling-induced bending generates sufficient force for selective degradation of one layer, leading to autonomous self-regulation associated with unbending. Our work helps define design criteria for molecularly controlled adaptive and self-regulating materials with embodied mechano-chemical information processing, and showcases their potential for adhesives and soft robotics
Mechano-adaptive meta-gels through synergistic chemical and physical information-processing
No full textGlobal functional adaptation after local mechanical stimulation, as in mechanobiology and the mimosa plant, is fascinating and ubiquitous in nature. This is achieved by locally sensing mechanical deformation with precise thresholds, processing this information via biochemical circuits, followed by downstream actuation. The integration of such embodied intelligence allowing for mechano-to-chemo-to-function information-processing remains elusive in man-made systems. By merging the fields of chemical circuits and metamaterials, we introduce adaptive metamaterial hydrogels (meta-gels) that can accurately sense mechanical stimuli (local touch and global strain), transmit this information over long distances via reaction-diffusion signaling, and induce downstream mechanical strengthening by growing nanofibril networks, or soft robotic actuation through competitive swelling. All elements of the sensor-processor-actuator system are embedded in the device, functioning autonomously without external feeding reservoirs. Our concept enables designing advanced life-like materials systems that synergistically combine two worlds – chemical circuits for chemical information-processing and metamaterial unit cells for physical information-processing
Mechano-Adaptive Meta-Gels Through Synergistic Chemical and Physical Information-Processing
No full textGlobal functional adaptation after local mechanical stimulation, as in mechanobiology and the mimosa plant, is fascinating and ubiquitous in nature. This is achieved by locally sensing mechanical deformation with precise thresholds, processing this information via biochemical circuits, followed by downstream actuation. The integration of such embodied intelligence allowing for mechano-to-chemo-to-function information-processing remains elusive in man-made systems. By merging the fields of chemical circuits and metamaterials, we introduce adaptive metamaterial hydrogels (meta-gels) that can accurately sense mechanical stimuli (local touch and global strain), transmit this information over long distances via reaction-diffusion signaling, and induce downstream mechanical strengthening by growing nanofibril networks, or soft robotic actuation through competitive swelling. All elements of the sensor-processor-actuator system are embedded in the device, functioning autonomously without external feeding reservoirs. Our concept enables designing advanced life-like materials systems that synergistically combine two worlds – chemical circuits for chemical information-processing and metamaterial unit cells for physical information-processing
Mechanoaktivierte Selbstauflösung von Hydrogelen mittels eines Signalverstärkungsmechanismus
No full textZelluläre Organismen verfügen über komplexe mechanoadaptive Systeme, die es ihnen ermöglichen, Kräfte zu spüren und sie mit (bio)chemischen Regelkreisläufen zur funktionellen Anpassung zu verarbeiten. Inspiriert durch solche Prozesse stellt diese Studie ein Hydrogelsystem vor, das zur mechanisch aktivierten und chemisch amplifizierten Selbstauflösung fähig ist. Die hierzu entwickelten Hydrogele können mechanisch Radikale erzeugen, die in einer sich selbst ausbreitenden radikalischen Entnetzungsreaktion verarbeitet und verstärkt werden, was letztendlich zu einer mechanisch ausgelösten Selbstauflösung führt. Wir setzen dieses System bei der mechanoinduzierten Ablösung und in einem Doppelschichtaktuator ein, bei dem die durch Schwellung verursachte Biegung ausreichend Kraft für den selektiven Abbau einer Schicht erzeugt, was zu einer autonomen Selbstregulierung im Zusammenhang mit der Entbiegung führt. Unsere Arbeit hilft bei der Definition von Designkriterien für molekular kontrollierte adaptive und selbstregulierende Materialien mit integrierter mechanochemischer Informationsverarbeitung und zeigt deren Potenzial für Adhäsive und die Soft Robotik auf
Urban Memory - Reload Company, ein wissenshaftligh-künstlerisches projekt zur begleitung städtischer veränderungsprozesse : am beispiel Dresdens
No full textCette thèse relate la conception d'une entreprise artiste créée par l'auteur, artiste entrepreneuse, dans l'intention de témoigner des mutations des villes et des choix effectués en matière de conservation ou de destruction. Urban Memory, entreprise de« rechargement en contenu mnémonique », a vu le jour en 2012 à Dresde, capitale saxonne, bombardée en 1945. Située à l'est de l'Allemagne, cette ville est en constant chantier depuis des décennies. C'est par l'intermédiaire d'une pratique artistique mêlant la peinture et la sérigraphie avec des moyens de communication mis en scène dans l'urbain qu'Urban Memory entend rendre compte des transformations du paysage architectural et accompagner les débats autour de l'identité et la mémoire de la ville. Dans une première partie, l'auteur retrace son parcours de découverte et de réflexion sur Dresde au travers de premiers travaux ; présente le contexte historique, politique et économique des mutations ; puis nous livre une analyse des entreprises artistes à partir de laquelle elle a conçu Urban Memory, son mode de fonctionnement et ses stratégies. Dans une seconde partie, l'auteur nous guide dans le centre historique de Dresde, le long de ses monuments et mémoriaux, afin de souligner tantôt l'éloquence, tantôt le silence dont sont capables de tels édifices et installations dans la ville ; puis se tourne vers la scène artistique contemporaine et ses moyens de création d'une mémoire « vivante ». Enfin, après avoir mis en lien ses propres outils artistiques et le contexte de sa recherche, l'auteur nous révèle les premières réalisations et les projets d'installation in situ de son entreprise.This thesis examines the author's conceptualization and establishment of an artist company with the objective of tracing urban transformations and of assessing decisions to conserve or destroy parts of the city. Urban Memory, a company that has as its goal the "recharging of mnemonic content," was founded in Saxony's capital city Dresden in 2012. Located in the east of Germany, this city, bombarded in 1945, has constantly been under construction in the past decades. Urban Memory takes account of the architectural landscape's transformations and accompanies debates about the identity and memory of the city. It does so by means of é hybrid form of artistic practices-painting and serigraphy-and communication media placed in the urban context. The first section of this thesis explores the artist's discovery and initial reflections on Dresden in the context of her first works; it explores the historical, political and economic context of the city's transformations; and it analyzes artist companies based on which Urban Memory has been conceived as well as its basic functional framework and strategic outlook. The second part zooms in on the historical center of Dresden, its monuments and memorial sites, so as to expose both the eloquence and silence with which the built environment of the city treats its past. Moreover, this part turns to the milieu of contemporary artists and their means of creating a 'living' memory. Finally, after having discussed and related the artistic dimension of her project, the author presents the company's first projects and in situ installations
Switchable Hydrophobic Pockets in DNA Protocells Enhance Chemical Conversion
No full textSynthetic cell models
help us understand living cells and the origin
of life. Key aspects of living cells are crowded interiors where secondary
structures, such as the cytoskeleton and membraneless organelles/condensates,
can form. These can form dynamically and serve structural or functional
purposes, such as protection from heat shock or as crucibles for various
biochemical reactions. Inspired by these phenomena, we introduce a
crowded all-DNA protocell and encapsulate a temperature-switchable
DNA-b-polymer block copolymer, in which the synthetic
polymer phase-segregates at elevated temperatures. We find that thermoreversible
phase segregation of the synthetic polymer occurs via bicontinuous
phase separation, resulting in artificial organelle structures that
can reorient into larger domains depending on the viscoelastic properties
of the protocell interior. Fluorescent sensors confirm the formation
of hydrophobic compartments, which enhance the reactivity of bimolecular
reactions. This study leverages the strengths of biological and synthetic
polymers to construct advanced biohybrid artificial cells that provide
insights into phase segregation under crowded conditions and the formation
of organelles and microreactors in response to environmental stress
Switchable Hydrophobic Pockets in DNA Protocells Enhance Chemical Conversion
No full textSynthetic cell models
help us understand living cells and the origin
of life. Key aspects of living cells are crowded interiors where secondary
structures, such as the cytoskeleton and membraneless organelles/condensates,
can form. These can form dynamically and serve structural or functional
purposes, such as protection from heat shock or as crucibles for various
biochemical reactions. Inspired by these phenomena, we introduce a
crowded all-DNA protocell and encapsulate a temperature-switchable
DNA-b-polymer block copolymer, in which the synthetic
polymer phase-segregates at elevated temperatures. We find that thermoreversible
phase segregation of the synthetic polymer occurs via bicontinuous
phase separation, resulting in artificial organelle structures that
can reorient into larger domains depending on the viscoelastic properties
of the protocell interior. Fluorescent sensors confirm the formation
of hydrophobic compartments, which enhance the reactivity of bimolecular
reactions. This study leverages the strengths of biological and synthetic
polymers to construct advanced biohybrid artificial cells that provide
insights into phase segregation under crowded conditions and the formation
of organelles and microreactors in response to environmental stress
Switchable Hydrophobic Pockets in DNA Protocells Enhance Chemical Conversion
No full textSynthetic cell models
help us understand living cells and the origin
of life. Key aspects of living cells are crowded interiors where secondary
structures, such as the cytoskeleton and membraneless organelles/condensates,
can form. These can form dynamically and serve structural or functional
purposes, such as protection from heat shock or as crucibles for various
biochemical reactions. Inspired by these phenomena, we introduce a
crowded all-DNA protocell and encapsulate a temperature-switchable
DNA-b-polymer block copolymer, in which the synthetic
polymer phase-segregates at elevated temperatures. We find that thermoreversible
phase segregation of the synthetic polymer occurs via bicontinuous
phase separation, resulting in artificial organelle structures that
can reorient into larger domains depending on the viscoelastic properties
of the protocell interior. Fluorescent sensors confirm the formation
of hydrophobic compartments, which enhance the reactivity of bimolecular
reactions. This study leverages the strengths of biological and synthetic
polymers to construct advanced biohybrid artificial cells that provide
insights into phase segregation under crowded conditions and the formation
of organelles and microreactors in response to environmental stress
The belief in a just world and distress at school
No full textThis article investigates the relationship between the belief in a just world (BJW) and distress at school. On the basis of just world theory, the authors argue that strong student BJW should be associated with low school distress. Two questionnaire studies with German secondary school students attending grades 7–13 are reported. Both studies found strong BJW to be associated with less distress at school, better grades, and the evaluation of grades and teachers as more just. Moreover, the relationship between strong BJW and low school distress persisted when controlled for grades, justice of grades, and teacher justice. This relationship held for all students, independently of their school track, grade level, or gender. Overall, the pattern of results reveals school distress to have a unique association with BJW and school-specific justice cognitions
Scalable approach to molecular motor-polymer conjugates for light-driven artificial muscles
No full textThe integration of molecular machines and motors into materials represents a promising avenue for creating dynamic and functional molecular systems, with potential applications in soft robotics or reconfigurable biomaterials. However, the development of truly scalable and controllable approaches for incorporating molecular motors into polymeric matrices has remained a challenge. Here, it is shown that light-driven molecular motors with sensitive photo-isomerizable double bonds can be converted into initiators for Cu-mediated controlled/living radical polymerization enabling the synthesis of star-shaped motor-polymer conjugates. This approach enables scalability, precise control over the molecular structure, block copolymer structures, and high-end group fidelity. Moreover, it is demonstrated that these materials can be crosslinked to form gels with quasi-ideal network topology, exhibiting light-triggered contraction. The influence of arm length and polymer structure is investigated, and the first molecular dynamics simulation framework to gain deeper insights into the contraction processes is developed. Leveraging this scalable methodology, the creation of bilayer soft robotic devices and cargo-lifting artificial muscles is showcased, highlighting the versatility and potential applications of this advanced polymer chemistry approach. It is anticipated that the integrated experimental and simulation framework will accelerate scalable approaches for active polymer materials based on molecular machines, opening up new horizons in materials science and bioscience
