Approaching intelligent infection diagnostics: Carbon fibre sensor for electrochemical pyocyanin detection

Sharp, Duncan; Gladstone, Patience; Smith, Robert B.; Forsythe, Stephen; Davis, James A.

doi:10.1016/j.bioelechem.2009.07.008

Cited by 116 publications

(111 citation statements)

References 30 publications

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“…Electrochemical detection of phenazines from liquid cultures of P. aeruginosa has been well established using various methods, including adsorptive stripping voltammetry (AdSV) 16 , differential pulse voltammetry (DPV) 17,19 , and SWV 18 . SECM approaches have also been employed 20 but cannot be effectively combined with voltage sweep techniques such as AdSV, DPV, and SWV for applications requiring quantification of concentration or detection of multiple species because of prohibitively long analysis times.…”

Section: Discussionmentioning

confidence: 99%

Integrated circuit-based electrochemical sensor for spatially resolved detection of redox-active metabolites in biofilms

et al. 2014

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Despite advances in monitoring spatiotemporal expression patterns of genes and proteins with fluorescent probes, direct detection of metabolites and small molecules remains challenging. A technique for spatially resolved detection of small molecules would benefit the study of redox-active metabolites produced by microbial biofilms, which can drastically affect colony development. Here we present an integrated circuit-based electrochemical sensing platform featuring an array of working electrodes and parallel potentiostat channels. “Images” over a 3.25 × 0.9 mm area can be captured with a diffusion-limited spatial resolution of 750 μm. We demonstrate that square wave voltammetry can be used to detect, identify, and quantify (for concentrations as low as 2.6 μM) four distinct redox-active metabolites called phenazines. We characterize phenazine production in both wild-type and mutant Pseudomonas aeruginosa PA14 colony biofilms, and find correlations with fluorescent reporter imaging of phenazine biosynthetic gene expression.

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Section: Discussionmentioning

confidence: 99%

Integrated circuit-based electrochemical sensor for spatially resolved detection of redox-active metabolites in biofilms

et al. 2014

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“…2A) important for P. aeruginosa virulence. Because it is under strict QS control (48) and can be detected electrochemically (45,52,54,55), pyocyanin can be used as a proxy for QS-mediated communication. To determine the number of bacteria required for P. aeruginosa to initiate QS, 8-pL microtraps were printed directly around one to five P. aeruginosa cells in situ (28), and the pyocyanin concentration was monitored by SECM imaging as the population grew over time.…”

Section: Resultsmentioning

confidence: 99%

“…(i) FcMeOH and pyocyanin have similar molecular weights (FcMeOH = 216.06; pyocyanin = 210.23), the same calculated Stokes radius of 0.33 nm (50,51), and diffusion coefficients of ∼7.5 × 10 6 cm/s (which were confirmed by the limiting current in the cyclic voltammograms collected in known concentrations of each molecule). (ii) A deposit formed on the surface of the ultramicroelectrode tip during the electrochemical reduction of oxidized pyocyanin (52,53), and this polymer formed a film that both created a larger capacitance and blocked the electrochemical reaction on the platinum surface, thus decreasing the current response. This polymerization did not affect our previous work (45), because a large ultramicroelectrode tip was used.…”

Section: Resultsmentioning

confidence: 99%

Real-time monitoring of quorum sensing in 3D-printed bacterial aggregates using scanning electrochemical microscopy

Connell

Kim

Shear

et al. 2014

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

166

162

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Microbes frequently live in nature as small, densely packed aggregates containing ∼10 1 -10 5 cells. These aggregates not only display distinct phenotypes, including resistance to antibiotics, but also, serve as building blocks for larger biofilm communities. Aggregates within these larger communities display nonrandom spatial organization, and recent evidence indicates that this spatial organization is critical for fitness. Studying single aggregates as well as spatially organized aggregates remains challenging because of the technical difficulties associated with manipulating small populations. Micro-3D printing is a lithographic technique capable of creating aggregates in situ by printing protein-based walls around individual cells or small populations. This 3D-printing strategy can organize bacteria in complex arrangements to investigate how spatial and environmental parameters influence social behaviors. Here, we combined micro-3D printing and scanning electrochemical microscopy (SECM) to probe quorum sensing (QS)-mediated communication in the bacterium Pseudomonas aeruginosa. Our results reveal that QS-dependent behaviors are observed within aggregates as small as 500 cells; however, aggregates larger than 2,000 bacteria are required to stimulate QS in neighboring aggregates positioned 8 μm away. These studies provide a powerful system to analyze the impact of spatial organization and aggregate size on microbial behaviors.Pseudomonas aeruginosa | scanning electrochemical microscopy | quorum sensing | 3D printing | pyocyanin B acterial populations are often found in nature as small, densely packed aggregates containing ∼10 1 -10 5 cells (1-5). These aggregates serve as building blocks for larger biofilm communities as well as a primary mode of transmission for pathogenic microbes (5-8). Similar to biofilm communities, aggregates develop microscale physical and chemical heterogeneity and display clinically relevant phenotypes, including enhanced antibiotic resistance (2,(8)(9)(10)(11)(12)(13)(14)(15)(16). Moreover, aggregate sizes containing as few as 10 3 bacteria have been shown to engage in quorum sensing (QS)-mediated behaviors (17-21). In its simplest form, QS is a communication strategy that allows bacteria to effectively monitor their population density through the secretion and sensing of extracellular signals (7,(22)(23)(24). When the population reaches a specific density, activation of the QS regulatory cascade results in enhanced transcription of a defined set of genes. These genes control distinct behaviors, including virulence, in the opportunistic pathogen Pseudomonas aeruginosa (25). In addition to displaying QS-mediated behaviors, bacterial aggregates have been shown to interact with neighboring aggregates both in vitro and in vivo (9,(26)(27)(28). Indeed, these interactions have a profound impact on virulence and are often mediated by small diffusible molecules (8-10, 22, 29-31).Despite the prevalence of aggregates in nature, understanding the mechanisms controlling their behavior and intera...

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“…The latter include: pH, [16][17][18][19][20] bacterial metabolites, [21][22][23] endogenous wound biomarkers, [ 24 ] volatile organic emissions [ 25,26 ] and temperature. [ 27 ] Many of these have been investigated with the intention of implementation within a clinic setting, but acquiring suffi cient selectivity with minimal sample preparation is a severe challenge, especially when considering the limited time available during a patient consultation.…”

Section: Electrochemical Solutionsmentioning

confidence: 99%

New Developments in Smart Bandage Technologies for Wound Diagnostics

et al. 2016

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The pH of wound fluid has long been recognized as an important diagnostic for assessing wound condition, but as yet there are few technological options available to the clinician. The availability of sensors that can measure wound pH, either in the clinic or at home could significantly improve clinical outcome - particularly in the early identification of complications such as infection. New material designs and electrochemical research strategies that are being targeted at wound diagnostics are identified and a critical overview of emerging research that could be pivotal in setting the direction for future devices is provided.

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Approaching intelligent infection diagnostics: Carbon fibre sensor for electrochemical pyocyanin detection

Cited by 116 publications

References 30 publications

Integrated circuit-based electrochemical sensor for spatially resolved detection of redox-active metabolites in biofilms

Integrated circuit-based electrochemical sensor for spatially resolved detection of redox-active metabolites in biofilms

Real-time monitoring of quorum sensing in 3D-printed bacterial aggregates using scanning electrochemical microscopy

New Developments in Smart Bandage Technologies for Wound Diagnostics

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