Surfactant sculpting of biologically inspired hierarchical surfaces

Morris, Melanie L.; Baird, Lance; Panigrahi, Asmi; Groß, Michael; Deacon, Ryan M.; Benkoski, Jason J.

doi:10.1039/c3sm52086b

Cited by 4 publications

(4 citation statements)

References 60 publications

(85 reference statements)

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“…Crystal violet staining [ 26 ] and subsequent quantitation showed that the preparative ethanol washes did not significantly reduce biofilm levels ( S1 Fig ). Finally, optical profilometry [ 27 ] was used to assess the biofilm depth on the surfaces analyzed by MALDI IMS ( S1 Fig ). Combined, these approaches indicated that the sample preparation methods for MALDI IMS did not significantly perturb biofilm integrity.…”

Section: Resultsmentioning

confidence: 99%

Adhesive Fiber Stratification in Uropathogenic Escherichia coli Biofilms Unveils Oxygen-Mediated Control of Type 1 Pili

et al. 2015

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Bacterial biofilms account for a significant number of hospital-acquired infections and complicate treatment options, because bacteria within biofilms are generally more tolerant to antibiotic treatment. This resilience is attributed to transient bacterial subpopulations that arise in response to variations in the microenvironment surrounding the biofilm. Here, we probed the spatial proteome of surface-associated single-species biofilms formed by uropathogenic Escherichia coli (UPEC), the major causative agent of community-acquired and catheter-associated urinary tract infections. We used matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) imaging mass spectrometry (IMS) to analyze the spatial proteome of intact biofilms in situ. MALDI-TOF IMS revealed protein species exhibiting distinct localizations within surface-associated UPEC biofilms, including two adhesive fibers critical for UPEC biofilm formation and virulence: type 1 pili (Fim) localized exclusively to the air-exposed region, while curli amyloid fibers localized to the air-liquid interface. Comparison of cells grown aerobically, fermentatively, or utilizing an alternative terminal electron acceptor showed that the phase-variable fim promoter switched to the “OFF” orientation under oxygen-deplete conditions, leading to marked reduction of type 1 pili on the bacterial cell surface. Conversely, S pili whose expression is inversely related to fim expression were up-regulated under anoxic conditions. Tethering the fim promoter in the “ON” orientation in anaerobically grown cells only restored type 1 pili production in the presence of an alternative terminal electron acceptor beyond oxygen. Together these data support the presence of at least two regulatory mechanisms controlling fim expression in response to oxygen availability and may contribute to the stratification of extracellular matrix components within the biofilm. MALDI IMS facilitated the discovery of these mechanisms, and we have demonstrated that this technology can be used to interrogate subpopulations within bacterial biofilms.

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Section: Resultsmentioning

confidence: 99%

Adhesive Fiber Stratification in Uropathogenic Escherichia coli Biofilms Unveils Oxygen-Mediated Control of Type 1 Pili

et al. 2015

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“…The entire process takes less than five minutes and can be used to create gradient surfaces. These include gradients in thickness, surface features, levels of hierarchy and surfactant concentrations [29].…”

Section: Introductionmentioning

confidence: 99%

“…This study used poly (dimethylsiloxane-diacrylate) (PDMS-DA), which can form surfaces that bear strong topographic resemblances to various tissue types [29]. Combined with its biocompatibility and the ability to tune its elastic modulus to match native tissue properties, PDMS-DA is a promising model system for probing cell-surface interactions [37].…”

Section: Introductionmentioning

confidence: 99%

Novel surfactant self-assembly process generates multi-scale surface topographies for stem cell growth and differentiation

Xie

Cook

Grayson

et al. 2018

Hem Ind

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Topographical features on a substrate can greatly influence stem cell fate through contact guidance. While the response of stem cells to topography at the nano-, micro-, and meso-scale has been studied extensively, little is known about the interplay of surface features acting simultaneously across multiple length scales. A limiting factor has been the availability of high throughput methods for probing the potentially unlimited parameter space. Herein we describe a facile method for rapidly generating a hierarchy of multi-scaled topographical features on polymer substrates via the self-assembly of surfactants at the monomer/water interface. Having previously assembled polydimethylsiloxane-diacrylate (PDMS-DA) into surfaces resembling multiple tissue morphologies, the current study refines this method to produce biocompatible substrates. To manage the large parameter space, we limit the scope of this study to surface features spanning nanometer (< 1 ?m) and micrometer (1-50 ?m) length scales, which arise both individually and in combination. Adipose-derived stem cells were plated onto five surface types and their morphology, proliferation, and osteogenic differentiation were assessed after non-inductive and osteogenic culture. We observed statistically significant differences in cellular responses to each surface. Among our observations, the increased osteogenesis of cells on surfaces with nano-scaled features superimposed over micro-scaled features suggests that such hierarchical surface structure mediates the osteogenic properties of a surface.

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“…In view of chemical systems, many kinds of fluidic flow under nonequilibrium conditions have been reported, some of which can be used as a model system for natural phenomena. One simple example is the Rayleigh–Taylor instability, which is seen when an interface between two liquids with different densities is placed in a gravitational field with a direction opposite to the density gradient. − The opposed gradient imposes the instability and fluidic flow at the interface, which is considered as the acceleration mechanism for thermonuclear flames in supernovae . In addition, Rayleigh–Bénard − and Bénard–Marangoni − instabilities are induced in the horizontal liquid layer with perpendicular temperature gradients.…”

Section: Introductionmentioning

confidence: 99%

One-Directional Fluidic Flow Induced by Chemical Wave Propagation in a Microchannel

et al. 2016

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A one-directional flow induced by chemical wave propagation was investigated to understand the origin of its dynamic flow. A cylindrical injection port was connected with a straight propagation channel; the chemical wave was initiated at the injection port. Chemical waves propagated with a constant velocity irrespective of the channel width, indicating that the dynamics of the chemical waves were governed by a geometry-independent interplay between the chemical reaction and diffusion. In contrast, the velocity of the one-directional flow was dependent on the channel width. Furthermore, enlargement of the injection port volume increased the flow velocity and volume flux. These results imply that the one-directional flow in the microchannel is due to a hydrodynamic effect induced in the injection port. Spectroscopic analysis of a pH indicator revealed the simultaneous behavior between the pH increase near the injection port and the one-directional flow. Hence, we can conclude that the one-directional flow in the microchannel with chemical wave propagation was caused by a proton consumption reaction in the injection port, probably through liquid volume expansion by the reaction products and the reaction heat. It is a characteristic feature of the present system that the hydrodynamic flow started from the chemical wave initiation point and not the propagation wavefront, as observed for previous systems.

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Surfactant sculpting of biologically inspired hierarchical surfaces

Cited by 4 publications

References 60 publications

Adhesive Fiber Stratification in Uropathogenic Escherichia coli Biofilms Unveils Oxygen-Mediated Control of Type 1 Pili

Adhesive Fiber Stratification in Uropathogenic Escherichia coli Biofilms Unveils Oxygen-Mediated Control of Type 1 Pili

Novel surfactant self-assembly process generates multi-scale surface topographies for stem cell growth and differentiation

One-Directional Fluidic Flow Induced by Chemical Wave Propagation in a Microchannel

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