Electrokinetics of Cells in Dielectrophoretic Separation: A Biological Perspective

Devi, Urmi; Puri, Paridhi; Sharma, Niti Nipun; Ananthasubramanian, M.

doi:10.1007/s12668-014-0140-y

Cited by 13 publications

(13 citation statements)

References 77 publications

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“…1 Due to their positive charge, these polymers can efficiently bind the negatively charged envelope of Gram-negative and Gram-positive bacteria. 2 At high concentrations and charge densities, these molecules have the potential to interfere with membrane integrity and decrease bacterial viability. 1 However, antimicrobial activity is heavily dependent on the length and nature of the polymer and, more importantly, on the nature of the targeted microbe.…”

Section: Introductionmentioning

confidence: 99%

Aggregation ofVibrio choleraeby cationic polymers enhances quorum sensing but over-rides biofilm dissipation in response to autoinduction

Pérez-Soto

Creese

Fernández-Trillo

et al. 2018

Preprint

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19Vibrio cholerae is a Gram-negative bacterium found in aquatic environments and a human 20 pathogen of global significance. Its transition between host-associated and environmental life 21 styles involves the tight regulation of niche-specific phenotypes such as motility, biofilm formation 22 and virulence. V. cholerae's transition from the host to environmental dispersal usually involves 23 suppression of virulence and dispersion of biofilm communities. In contrast to this naturally 24 occurring transition, bacterial aggregation by cationic polymers triggers a unique response, which 25 is to suppress virulence gene expression while also triggering biofilm formation by V. cholerae, 26 an artificial combination of traits that is potentially very useful to bind and neutralize the pathogen 27 from contaminated water. Here, we set out to uncover the mechanistic basis of this polymer-28 triggered bacterial behavior. We found that bacteria-polymer aggregates undergo rapid 29 autoinduction and achieve quorum sensing at bacterial densities far below those required for 30 autoinduction in the absence of polymers. We demonstrate this induction of quorum sensing is due 31 both to a rapid formation of autoinducer gradients and local enhancement of autoinducer 32 concentrations within bacterial clusters, as well as the stimulation of CAI-1 and AI-2 production 33 by aggregated bacteria. We further found that polymers cause an induction of the biofilm specific 34 regulator VpsR and the biofilm structural protein RbmA, bypassing the usual suppression of 35 biofilm during autoinduction. Overall, this study highlights that synthetic materials can be used to 36 cross-wire natural bacterial responses to achieve a combination of phenotypes with potentially 37 useful applications. 38 39 40 41 Polymers and quorum sensing in V. cholerae 42 Both natural and synthetic cationic macromolecules, such as cationic antimicrobial peptides, 43 cationic polymers and dendrimers, have been extensively reported as antimicrobial. 1 Due to their 44 positive charge, these polymers can efficiently bind the negatively charged envelope of Gram-45 negative and Gram-positive bacteria. 2 At high concentrations and charge densities, these molecules 46 have the potential to interfere with membrane integrity and decrease bacterial viability. 1 However, 47 antimicrobial activity is heavily dependent on the length and nature of the polymer and, more 48 importantly, on the nature of the targeted microbe. At low concentrations, cationic polymers are 49 still capable of causing bacterial aggregation by mediating electrostatic interactions, but do so 50 without significantly affecting bacterial membrane integrity and growth. 3 51 We and others have previously reported that bacteria clustered by sub-inhibitory 52 concentrations of cationic polymers display interesting phenotypes resembling those of biofilm 53 communities. 3 For instance, we have recently demonstrated that clustering of the diarrheal 54 pathogen Vibrio cholerae with methacrylamides containing primar...

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Section: Introductionmentioning

confidence: 99%

Aggregation ofVibrio choleraeby cationic polymers enhances quorum sensing but over-rides biofilm dissipation in response to autoinduction

Pérez-Soto

Creese

Fernández-Trillo

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

“… 1 − 3 Because of their positive charge, these polymers can efficiently bind the negatively charged envelope of Gram-negative and Gram-positive bacteria. 4 − 6 At high concentrations and charge densities, these molecules have the potential to interfere with membrane integrity and decrease bacterial viability. 1 − 3 However, antimicrobial activity is heavily dependent on the length and nature of the polymer and, more importantly, on the nature of the targeted microbe.…”

mentioning

confidence: 99%

Aggregation of Vibrio cholerae by Cationic Polymers Enhances Quorum Sensing but Overrides Biofilm Dissipation in Response to Autoinduction

et al. 2018

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Vibrio cholerae is a Gram-negative bacterium found in aquatic environments and a human pathogen of global significance. Its transition between host-associated and environmental lifestyles involves the tight regulation of niche-specific phenotypes such as motility, biofilm formation, and virulence. V. cholerae’s transition from the host to environmental dispersal usually involves suppression of virulence and dispersion of biofilm communities. In contrast to this naturally occurring transition, bacterial aggregation by cationic polymers triggers a unique response, which is to suppress virulence gene expression while also triggering biofilm formation by V. cholerae, an artificial combination of traits that is potentially very useful to bind and neutralize the pathogen from contaminated water. Here, we set out to uncover the mechanistic basis of this polymer-triggered bacterial behavior. We found that bacteria–polymer aggregates undergo rapid autoinduction and achieve quorum sensing at bacterial densities far below those required for autoinduction in the absence of polymers. We demonstrate this induction of quorum sensing is due both to a rapid formation of autoinducer gradients and local enhancement of autoinducer concentrations within bacterial clusters as well as the stimulation of CAI-1 and AI-2 production by aggregated bacteria. We further found that polymers cause an induction of the biofilm-specific regulator VpsR and the biofilm structural protein RbmA, bypassing the usual suppression of biofilm during autoinduction. Overall, this study highlights that synthetic materials can be used to cross-wire natural bacterial responses to achieve a combination of phenotypes with potentially useful applications.

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“…The use of dielectrophoretic force with microfluidics for continuous particle separation has advantages such as low cost, rapidity, size sensitivity, and selectivity. Previously published reviews discuss a variety of techniques used for dielectrophoretics-based cell and particle separation [ 77 , 78 , 79 , 80 , 81 ]. Cui et al [ 82 ] proposed a dielectrophoresis (DEP)-based method for size-based particle separation.…”

Section: Continuous Flow Microfluidicsmentioning

confidence: 99%

Recent Advances and Future Perspectives on Microfluidic Liquid Handling

et al. 2017

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The interdisciplinary research field of microfluidics has the potential to revolutionize current technologies that require the handling of a small amount of fluid, a fast response, low costs and automation. Microfluidic platforms that handle small amounts of liquid have been categorised as continuous-flow microfluidics and digital microfluidics. The first part of this paper discusses the recent advances of the two main and opposing applications of liquid handling in continuous-flow microfluidics: mixing and separation. Mixing and separation are essential steps in most lab-on-a-chip platforms, as sample preparation and detection are required for a variety of biological and chemical assays. The second part discusses the various digital microfluidic strategies, based on droplets and liquid marbles, for the manipulation of discrete microdroplets. More advanced digital microfluidic devices combining electrowetting with other techniques are also introduced. The applications of the emerging field of liquid-marble-based digital microfluidics are also highlighted. Finally, future perspectives on microfluidic liquid handling are discussed.

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Electrokinetics of Cells in Dielectrophoretic Separation: A Biological Perspective

Cited by 13 publications

References 77 publications

Aggregation ofVibrio choleraeby cationic polymers enhances quorum sensing but over-rides biofilm dissipation in response to autoinduction

Aggregation ofVibrio choleraeby cationic polymers enhances quorum sensing but over-rides biofilm dissipation in response to autoinduction

Aggregation of Vibrio cholerae by Cationic Polymers Enhances Quorum Sensing but Overrides Biofilm Dissipation in Response to Autoinduction

Recent Advances and Future Perspectives on Microfluidic Liquid Handling

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