Geometrical frustration of phase-separated domains in<i>Coscinodiscus</i>diatom frustules

Feofilova, Maria; Schüepp, Silvan; Schmid, Rudi; Hacker, Florian; Spanke, Hendrik T.; Bain, Nicolas; Jensen, Katharine; Dufresne, Eric R.

doi:10.1073/pnas.2201014119

Cited by 8 publications

(5 citation statements)

References 51 publications

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“…(ii) Previously, it has been assumed that silica morphogenesis inside the valve SDV is dependent on directional influx of silica precursor [47]. Similarly, it was proposed that cytoskeletal fibers may guide pattern formation [26], [48]. While the cytoskeleton could contribute to material delivery to the SDV and determining SDV shape, our model shows that neither directed silica influx nor a direct guidance role of cytoskeletal fibers is required to explain the formation of radial rib patterns.…”

Section: Discussionmentioning

confidence: 58%

“…This yields N b (r) = N b (0)+2π r/d for the expected number of branching points in a valve of area A = π r 2 , up to a constant offset N b (0) which corresponds to stem branching points of the annulus. A similar geometric law was previously applied to the number of defects in pore patterns of diatom valves [26]. Mathematical description.…”

Section: Resultsmentioning

confidence: 99%

“…Other studies investigated phase-separation as a mechanism for valve morphogenesis addressing formation of pores [23], [24] but did not account for branching patterns of silica. Others put their efforts exclusively on studying the formation of regular pore patterns assuming a pre-pattern of silica ribs [23], [25], [26].…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of branching morphogenesis inspired by diatom silica formation

Babenko

Kröger

Friedrich

2023

Preprint

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The silica-based cell walls of diatoms are prime examples of genetically controlled, species-specific mineral architectures. The physical principles underlying morphogenesis of their hierarchically structured silica patterns are not understood, yet such insight could indicate novel routes towards synthesizing functional inorganic materials. Recent advances in imaging nascent diatom silica allow rationalizing possible mechanisms of their pattern formation. Here, we combine theory and experiments on the model diatom Thalassiosira pseudonana to put forward a minimal model of branched rib patterns - a fundamental feature of the silica cell wall. We quantitatively recapitulate the time-course of rib pattern morphogenesis by accounting for silica biochemistry with autocatalytic formation of diffusible silica precursors followed by conversion into solid silica. We propose that silica deposition releases an inhibitor that slows down up-stream precursor conversion, thereby implementing a self-replicating reaction-diffusion system as a non-classical Turing mechanism. The proposed mechanism highlights the role of geometrical cues for guided self-organization, rationalizing the instructive role for the single initial pattern seed known as primary silicification site. The mechanism of branching morphogenesis that we characterize here is possibly generic and may apply also in other biological systems.

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Section: Discussionmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 99%

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Mechanism of branching morphogenesis inspired by diatom silica formation

Babenko

Kröger

Friedrich

2023

Preprint

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“…Some examples include the photonic structures generating color in some bird feathers, [15][16][17][18] the topography of pollen's cell walls, [19] and the regular porosity of diatom frustules. [20][21][22] We have previously shown that polymerization-induced phase separation in the solid state can be used to make durable, nanostructured, and colorful materials. [23] This process starts with a glassy polymer matrix swollen and plasticized with a second monomer.…”

Section: Macromolecular Materials Often Possess Highly Desirablementioning

confidence: 99%

“…For example, cells generate structures with pronounced order and low size dispersity through phase separation. Some examples include the photonic structures generating color in some bird feathers, [15–18] the topography of pollen's cell walls, [19] and the regular porosity of diatom frustules [20–22] . We have previously shown that polymerization‐induced phase separation in the solid state can be used to make durable, nanostructured, and colorful materials [23] .…”

Section: Figurementioning

confidence: 99%

ATRP Enhances Structural Correlations In Polymerization‐Induced Phase Separation**

et al. 2023

Self Cite

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Synthetic methods to control the structure of materials at sub-micron scales are typically based on the self-assembly of structural building blocks with precise size and morphology. On the other hand, many living systems can generate structure across a broad range of length scales in one step directly from macromolecules, using phase separation. Here, we introduce and control structure at the nano-and microscales through polymerization in the solid state, which has the unusual capability of both triggering and arresting phase separation. In particular, we show that atom transfer radical polymerization (ATRP) enables control of nucleation, growth, and stabilization of phase-separated poly-methylmethacrylate (PMMA) domains in a solid polystyrene (PS) matrix. ATRP yields durable nanostructures with low size dispersity and high degrees of structural correlations. Furthermore, we demonstrate that the length scale of these materials is controlled by the synthesis parameters.

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Hexagonal Patterns in Diatom Silica Form via a Directional Two‐Step Process

Lansky,

de Haan,

Piven

et al. 2024

Advanced Science

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Organisms are able to control material patterning down to the nanometer scale. This is exemplified by the intricate geometrical patterns of the silica cell wall of diatoms, a group of unicellular algae. Theoretical and modeling studies propose putative physical and chemical mechanisms to explain morphogenesis of diatom silica. Nevertheless, direct investigations of the underlying formation process are challenging because this process occurs within the confines of the living cell. Here, a method is developed for in situ 3D visualization of silica development in the diatom Stephanopyxis turris, using electron microscopy slice‐and‐view techniques. The formation of an isotropic hexagonal pattern made of nanoscale pores is documented. Surprisingly, these data reveal a directional process that starts with elongation of silica rods along one of the three equivalent orientations of the hexagonal lattice. Only as a secondary step, these rods are connected by crisscrossing bridges that give rise to the complete hexagonal pattern. These in situ observations combine two known properties of diatom silica, close packing of pores and branching of rods, to a unified process that yields isotropic patterns from an anisotropic background. Future research into diatom morphogenesis should focus on rod elongation and branching as the key for pattern formation.

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Geometrical frustration of phase-separated domains inCoscinodiscusdiatom frustules

Cited by 8 publications

References 51 publications

Mechanism of branching morphogenesis inspired by diatom silica formation

Mechanism of branching morphogenesis inspired by diatom silica formation

ATRP Enhances Structural Correlations In Polymerization‐Induced Phase Separation**

Hexagonal Patterns in Diatom Silica Form via a Directional Two‐Step Process

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