Elasticity-mediated nematiclike bacterial organization in model extracellular DNA matrix

Smalyukh, Ivan I.; Butler, John C.; Shrout, Joshua D.; Parsek, Matthew R.; Wong, Gerard C. L.

doi:10.1103/physreve.78.030701

Cited by 73 publications

(90 citation statements)

References 36 publications

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“…P. aeruginosa cells have been shown to spontaneously orient with the direction of extended, concentrated DNA molecules (35). Our time-lapse imaging of interstitial biofilm expansion in the presence of the eDNA stain TOTO-1 revealed that as cells migrated through areas of high eDNA content, they dragged the eDNA along, causing it to be generally aligned with the direction of cell movement (Fig.…”

Section: Discussionmentioning

confidence: 93%

Self-organization of bacterial biofilms is facilitated by extracellular DNA

Gloag¹,

Turnbull²,

Huang

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

257

269

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Twitching motility-mediated biofilm expansion is a complex, multicellular behavior that enables the active colonization of surfaces by many species of bacteria. In this study we have explored the emergence of intricate network patterns of interconnected trails that form in actively expanding biofilms of Pseudomonas aeruginosa. We have used high-resolution, phase-contrast time-lapse microscopy and developed sophisticated computer vision algorithms to track and analyze individual cell movements during expansion of P. aeruginosa biofilms. We have also used atomic force microscopy to examine the topography of the substrate underneath the expanding biofilm. Our analyses reveal that at the leading edge of the biofilm, highly coherent groups of bacteria migrate across the surface of the semisolid media and in doing so create furrows along which following cells preferentially migrate. This leads to the emergence of a network of trails that guide mass transit toward the leading edges of the biofilm. We have also determined that extracellular DNA (eDNA) facilitates efficient traffic flow throughout the furrow network by maintaining coherent cell alignments, thereby avoiding traffic jams and ensuring an efficient supply of cells to the migrating front. Our analyses reveal that eDNA also coordinates the movements of cells in the leading edge vanguard rafts and is required for the assembly of cells into the "bulldozer" aggregates that forge the interconnecting furrows. Our observations have revealed that large-scale self-organization of cells in actively expanding biofilms of P. aeruginosa occurs through construction of an intricate network of furrows that is facilitated by eDNA.collective behavior | t4p | type IV pili | tfp | swarming

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Section: Discussionmentioning

confidence: 93%

Self-organization of bacterial biofilms is facilitated by extracellular DNA

Gloag¹,

Turnbull²,

Huang

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

257

269

View full text Add to dashboard Cite

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“…43,44 Additionally, the patterns and order induced in theses LCLC films could be transferred to suspended colloids, suspended nanotubes and bacterial systems to create novel metamaterial films. [21][22][23][24][25] …”

Section: -9 |mentioning

confidence: 99%

“…As a result, their mesophases differ significantly from thermotropic and amphiphilic lyotropic liquid crystals. Patterned films of LCLCs have a wide variety of emerging applications distinct from other types of liquid crystals, including inexpensive polarizing films, [12][13][14] holographic displays, 15,16 organic electronics and solar cells, 17,18 biosensors, 19,20 , aqueous colloidal, nanotube and bacterial assembly, [21][22][23][24][25] and precursors to structured graphene-based materials. 26,27 LCLCs also offer useful attributes for fundamental investigation of the effects of elasticity on self-assembly behavior, since their elastic properties can be tuned via control of mesogen concentration, 28 depletants and ions.…”

Section: Introductionmentioning

confidence: 99%

Elasticity-dependent self-assembly of micro-templated chromonic liquid crystal films

et al. 2014

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We explore micropatterned director structures of aqueous lyotropic chromonic liquid crystal (LCLC) films created on squarelattice cylindrical-micropost substrates. The structures are manipulated by modulating the LCLC mesophases and their elastic properties via concentration through drying. Nematic LCLC films exhibit preferred bistable alignment along the diagonals of the micropost lattice. Columnar LCLC films, dried from nematics, form two distinct director and defect configurations: a diagonally aligned director pattern with local squares of defects, and an off-diagonal configuration with zig-zag defects. The formation of these states appears to be tied to the relative splay and bend free energy costs of the initial nematic films. The observed nematic and columnar configurations are understood numerically using a Landau-de Gennes free energy model. Among other attributes, the work provide first examples of quasi-2D micropatterning of LC films in the columnar phase and lyotropic LC films in general, and it demonstrates alignment and configuration switching of typically difficult-to-align LCLC films via bulk elastic properties.

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“…23,24 For the nematic LC, assuming that the Frank elastic constants for splay, twist, and bend are equal to their average value K, the elastic energy cost of rod realignment 23 to an angle θ from its equilibrium θ ) 0 orientation can be estimated as ∆F elastic ≈ 2πKθ 2 L/ln[2L/R] (note that the rods studied here have rather small aspect ratios and only rough estimates are possible by using this equation). Taking K ≈ 1pN (typical for lyotropic nematics) and dimensions of GNRs, one finds ∆F elastic ≈ 3 × 10 -19 θ 2 J larger than the thermal energy K B T unless θ is very small.…”

mentioning

confidence: 99%

Self-Alignment of Plasmonic Gold Nanorods in Reconfigurable Anisotropic Fluids for Tunable Bulk Metamaterial Applications

et al. 2010

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We demonstrate the bulk self-alignment of dispersed gold nanorods imposed by the intrinsic cylindrical micelle selfassembly in nematic and hexagonal liquid crystalline phases of anisotropic fluids. External magnetic field and shearing allow for alignment and realignment of the liquid crystal matrix with the ensuing long-range orientational order of well-dispersed plasmonic nanorods. This results in a switchable polarization-sensitive plasmon resonance exhibiting stark differences from that of the same nanorods in isotropic fluids. The device-scale bulk nanoparticle alignment may enable optical metamaterial mass production and control of properties arising from combining the switchable nanoscale structure of anisotropic fluids with the surface plasmon resonance properties of the plasmonic nanorods.KEYWORDS Nanorods, liquid crystals, optical metamaterials, self-assembly, plasmonic nanoparticles H aving predesigned structural units different from those in a conventional matter, metamaterials exhibit many unusual properties of interest from both fundamental science and applications standpoints. However, manufacturing such bulk optical metamaterials with three-dimensional (3D) structure 1-4 using lithography techniques presents a significant challenge, especially for the large-scale production. Mass production of bulk optical metamaterials from self-aligning and self-assembling nanoparticles is poised to revolutionize scientific instruments, technologies,andconsumerdevices.5-7 Althoughthemetamaterial self-assembly from nanoparticles remains a significant challenge, recent advances in colloidal science show that it may be realized and the emerging nanoscale alignment and assembly approaches utilize surface monolayers, 8,9 stretched polymer films, 10,11 and functionalized nanoparticles 12,13 but are usually restricted to only short-range ordering, twodimensional rather than three-dimensional assembly, and limited switching.7 Tunable metamaterials may potentially be obtained by nanoparticle self-assembly in liquid crystals (LCs) 14 through the LC-mediated realignment and rearrangement of incorporated nanoparticles in response to applied fields. However, experimental realization of such self-assembling switchable metamaterial composites is lacking. In this work, we demonstrate spontaneous long-range orientational ordering of gold nanorods (GNRs) dispersed in surfactant-based lyotropic LCs and use polarizing optical microscopy, darkfield microscopy, spectroscopy, and freezefracture transmission electron microscopy (FFTEM) to study these composites on the scales ranging from nanometers to millimeters. We find that the anisotropic fluids in both columnar hexagonal and nematic LC phases impose nematic-like long-range orientational ordering of GNRs with no correlation of their centers of mass but with the GNRs aligning along the LC director n (a unit vector describing the average local orientation of cylindrical micelles forming the LC), Figure 1. The unidirectional alignment of nanorods with high order parameter is...

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Elasticity-mediated nematiclike bacterial organization in model extracellular DNA matrix

Cited by 73 publications

References 36 publications

Self-organization of bacterial biofilms is facilitated by extracellular DNA

Self-organization of bacterial biofilms is facilitated by extracellular DNA

Elasticity-dependent self-assembly of micro-templated chromonic liquid crystal films

Self-Alignment of Plasmonic Gold Nanorods in Reconfigurable Anisotropic Fluids for Tunable Bulk Metamaterial Applications

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