Designing complex local properties that seamlessly integrate efficient functions into processed materials presents a formidable challenge. A promising solution has emerged in the form of ultrafast ...laser‐surface structuring. Through time‐controlled polarization ultrafast irradiation at the picosecond timescale, spontaneous self‐organization of surfaces can be induced. The thermal gradient length scale unfolds on the micro‐ and nanoscale, instigating thermoconvection that leads to structured surfaces upon quenching. Convective instabilities dynamically shape intricate yet self‐regulated periodic relief structures. The ability to achieve laser‐induced self‐organization in both surface dimensions holds immense scientific importance, as it unlocks the potential to create uniform periodic 2D patterns by harnessing the inherent regulation of nonlinear dynamics processes in fluids. This comprehensive review explores recent advances in understanding and leveraging ultrafast laser‐induced self‐organization for precise patterning across versatile scales and applications. The insights herein hold the potential to drive significant advancements in nanoscale manufacturing through 2D laser‐induced periodic surface structures.
Ultrafast laser structuring offers a promising solution for creating a wide array of complex surface morphologies. Through time‐controlled polarization ultrafast irradiation, surfaces can spontaneously self‐organize at the micro‐ and nanoscale. Explored in a comprehensive review, this technique unlocks the potential to create precise 2D patterns, propelling advancements in nanoscale manufacturing.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Self‐assembly, the spontaneous ordering of components into patterns, is widespread in nature and fundamental to generating function across length scales. Morphogen gradients in biological development ...are paradigmatic as both products and effectors of self‐assembly and various attempts have been made to reproduce such gradients in biomaterial design. To date, approaches have typically utilized top‐down fabrication techniques that, while allowing high‐resolution control, are limited by scale and require chemical cross‐linking steps to stabilize morphogen patterns in time. Here, a bottom‐up approach to protein patterning is developed based on a novel binary reaction‐diffusion process where proteins function as diffusive reactants to assemble a nanoclay‐protein composite hydrogel. Using this approach, it is possible to generate scalable and highly stable 3D patterns of target proteins down to sub‐cellular resolution through only physical interactions between clay nanoparticles and the proteins and ions present in blood. Patterned nanoclay gels are able to guide cell behavior to precisely template bone tissue formation in vivo. These results demonstrate the feasibility of stabilizing 3D gradients of biological signals through self‐assembly processes and open up new possibilities for morphogen‐based therapeutic strategies and models of biological development and repair.
A new reaction‐diffusion self‐assembly system in which proteins function as diffusive reactants to assemble stable clay‐protein composite hydrogels is reported. The opportunity to exploit this system to assemble stable 3D patterning of bioactive proteins with high protein loading, resolution, and scalability is demonstrated.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Polyaniline (PANI) is prepared by the oxidation of aniline. Depending on the acidity conditions during the chemical oxidation, different types of products can be identified. The aniline dimers, ...semidines, are the first oxidation products. In the next step, aniline trimers containing a phenazine moiety, the nucleates, are produced. At moderate acidity, pH
>
3.5, the reaction pathway further leads to higher brown non-conducting aniline oligomers. Alternatively, when the acidity is sufficiently high, pH
<
2.5, the nucleates convert to initiation centers that start the subsequent propagation of PANI chains.
The model of phenazine nucleates is offered to explain the various supramolecular nanostructures produced by PANI. It is proposed that the hydrophobic nucleates randomly aggregate in the aqueous phase or become organized to form one-dimensional stacks stabilized by π–π interactions. This step is followed by the growth of PANI chains from the self-assembled nucleates. The evolution of the nanostructures is conveniently observed by the combination of microscopic and spectroscopic techniques. The random agglomeration of nucleates gives rise to PANI granules and regular self-assembly into stacks subsequently leads to PANI nanofibers. The growth of other nanostructures requires a starting template. A model of a flowing template combined with a helical nanotubular growth is proposed to account for the formation of nanotubes, monomer droplets serve as templates for microspheres. The detailed chemical structure of nucleates has still to be elucidated.
The nucleates adsorb and self-assemble along various interfaces giving subsequently rise to additional conducting polymer morphologies. The adsorption of nucleates at solid surfaces immersed in the reaction mixture leads to PANI nanofilms or coatings of various substrates. The competition between nucleate adsorption and nucleate self-assembly may lead to more complex morphologies combining one-dimensional and three-dimensional features, such as nanobrushes, hairy spheres,
etc. The control of nucleates self-assembly and of PANI growth, the involvement of various interfaces in this process, and the role of PANI conductivity are discussed.
The nanostructures produced by other conducting polymers, especially by substituted PANI, polypyrrole, or poly(3,4-ethylenedioxythiophene) are also considered. Two potential extensions to the preparation of related materials, such as nitrogen-containing carbonized PANI nanostructures or the composites of conducting polymers with noble metals are outlined. The present review accounts for the latest development in the realm of PANI nanostructures in past few years and provides an upgrade in the models proposed for their formation.
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The capability to organize matter in spontaneous periodic patterns under the action of light is critical in achieving laser structuring on sub-wavelength scales. Here, the phenomenon ...of light coupling to Marangoni convection flows is reported in an ultrashort laser-melted surface nanolayer destabilized by rarefaction wave resulting in the emergence of polarization-sensitive regular nanopatterns. Coupled electromagnetic and compressible Navier-Stokes simulations are performed in order to evidence that the transverse temperature gradients triggered by non-radiative optical response of surface topography are at the origin of Marangoni instability-driven self-organization of convection nanocells and high spatial frequency periodic structures on metal surfaces, with dimensions down to λ/15 (λ being the laser wavelength) given by Marangoni number and melt layer thickness. The instability-driven organization of matter occurs in competition with electromagnetic feedback driven by material removal in positions of the strongest radiative field enhancement. Upon this feedback, surface topography evolves into low spatial frequency periodic structures, conserving the periodicity provided by light interference.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Self‐organization is a process by which interacting cells organize and arrange themselves in higher order structures and patterns. To achieve this, cells must have molecular mechanisms to sense their ...complex local environment and interpret it to respond accordingly. A combination of cell‐intrinsic and cell‐extrinsic cues are decoded by the single cells dictating their behaviour, their differentiation and symmetry‐breaking potential driving development, tissue remodeling and regenerative processes. A unifying property of these self‐organized pattern‐forming systems is the importance of fluctuations, cell‐to‐cell variability, or noise. Cell‐to‐cell variability is an inherent and emergent property of populations of cells that maximize the population performance instead of the individual cell, providing tissues the flexibility to develop and maintain homeostasis in diverse environments. In this review, we will explore the role of self‐organization and cell‐to‐cell variability as fundamental properties of multicellularity—and the requisite of single‐cell resolution for its understanding. Moreover, we will analyze how single cells generate emergent multicellular dynamics observed at the tissue level ‘travelling’ across different scales: spatial, temporal and functional.
Self‐organization is the process by which interacting cells organize and arrange themselves in higher order structures and patterns providing tissues the flexibility to develop and regenerate in varying environments. We explore here how single cells and their heterogeneity generate robust emergent multicellular structures and we discuss the need of techniques with single‐cell resolution to understand self‐organization across spatial, temporal and functional scales.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
57.
Landscapes of facilitation Cornacchia, Loreta; Van De Koppel, Johan; Van Der Wal, Daphne ...
Ecology (Durham),
April 2018, Volume:
99, Issue:
4
Journal Article
Peer reviewed
Open access
Spatial heterogeneity plays a crucial role in the coexistence of species. Despite recognition of the importance of self-organization in creating environmental heterogeneity in otherwise uniform ...landscapes, the effects of such self-organized pattern formation in promoting coexistence through facilitation are still unknown. In this study, we investigated the effects of pattern formation on species interactions and community spatial structure in ecosystems with limited underlying environmental heterogeneity, using self-organized patchiness of the aquatic macrophyte Callitriche platycarpa in streams as a model system. Our theoretical model predicted that pattern formation in aquatic vegetation – due to feedback interactions between plant growth, water flow and sedimentation processes – could promote species coexistence, by creating heterogeneous flow conditions inside and around the plant patches. The spatial plant patterns predicted by our model agreed with field observations at the reach scale in naturally vegetated rivers, where we found a significant spatial aggregation of two macrophyte species around C. platycarpa. Field transplantation experiments showed that C. platycarpa had a positive effect on the growth of both beneficiary species, and the intensity of this facilitative effect was correlated with the heterogeneous hydrodynamic conditions created within and around C. platycarpa patches. Our results emphasize the importance of self-organized patchiness in promoting species coexistence by creating a landscape of facilitation, where new niches and facilitative effects arise in different locations. Understanding the interplay between competition and facilitation is therefore essential for successful management of biodiversity in many ecosystems.
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BFBNIB, FZAB, GIS, IJS, INZLJ, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZRSKP
Light-activated self-propelled colloids Palacci, J.; Sacanna, S.; Kim, S.-H. ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
11/2014, Volume:
372, Issue:
2029
Journal Article
Peer reviewed
Open access
Light-activated self-propelled colloids are synthesized and their active motion is studied using optical microscopy. We propose a versatile route using different photoactive materials, and ...demonstrate a multiwavelength activation and propulsion. Thanks to the photoelectrochemical properties of two semiconductor materials (α-Fe2O3 and TiO2), a light with an energy higher than the bandgap triggers the reaction of decomposition of hydrogen peroxide and produces a chemical cloud around the particle. It induces a phoretic attraction with neighbouring colloids as well as an osmotic self-propulsion of the particle on the substrate. We use these mechanisms to form colloidal cargos as well as self-propelled particles where the light-activated component is embedded into a dielectric sphere. The particles are self-propelled along a direction otherwise randomized by thermal fluctuations, and exhibit a persistent random walk. For sufficient surface density, the particles spontaneously form ‘living crystals’ which are mobile, break apart and reform. Steering the particle with an external magnetic field, we show that the formation of the dense phase results from the collisions heads-on of the particles. This effect is intrinsically non-equilibrium and a novel principle of organization for systems without detailed balance. Engineering families of particles self-propelled by different wavelength demonstrate a good understanding of both the physics and the chemistry behind the system and points to a general route for designing new families of self-propelled particles.
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During neural tube (NT) development, the notochord induces an organizer, the floorplate, which secretes Sonic Hedgehog (SHH) to pattern neural progenitors. Conversely, NT organoids (NTOs) from ...embryonic stem cells (ESCs) spontaneously form floorplates without the notochord, demonstrating that stem cells can self-organize without embryonic inducers. Here, we investigated floorplate self-organization in clonal mouse NTOs. Expression of the floorplate marker FOXA2 was initially spatially scattered before resolving into multiple clusters, which underwent competition and sorting, resulting in a stable “winning” floorplate. We identified that BMP signaling governed long-range cluster competition. FOXA2+ clusters expressed BMP4, suppressing FOXA2 in receiving cells while simultaneously expressing the BMP-inhibitor NOGGIN, promoting cluster persistence. Noggin mutation perturbed floorplate formation in NTOs and in the NT in vivo at mid/hindbrain regions, demonstrating how the floorplate can form autonomously without the notochord. Identifying the pathways governing organizer self-organization is critical for harnessing the developmental plasticity of stem cells in tissue engineering.
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•During neural tube organoid self-organization, scattered FOXA2+ cells form clusters•FOXA2+ clusters compete via long-range signaling to establish a "winning" floorplate•BMP4 and NOGGIN control numbers and sizes of FOXA2+ clusters•NOGGIN is functionally involved in controlling floorplate size in vivo
Krammer et al. show that retinoic-acid-triggered self-organization of neural tube organoids occurs via induction of scattered FOXA2-expressing cells that undergo clustering and competition to persist and form floorplates. Cluster competition occurs via BMP signaling, which controls floorplate number and size in vitro and size in vivo at the mid/hindbrain region.
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