Novel dual Pt-Pt/IrO  ultramicroelectrode for pH imaging using SECM in both potentiometric and amperometric modes

Zhu, Zejie; Ye, Zhenni; Zhang, Qinhao; Cao, Fahe

doi:10.1016/j.elecom.2018.01.018

Cited by 35 publications

(11 citation statements)

References 23 publications

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“…This sensor was successfully applied to study the localized pH distribution during the corrosion of stainless steel in NaCl solution by SECM. The same group proposed a dual solid-state microelectrode that can be used in both amperometric and potentiometric SECM modes 156. As above,the amperometric mode allows one to control tip-substrate distance while the potentiometric mode provides information on ion distribution.…”

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confidence: 99%

Potentiometric Sensing

2018

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confidence: 99%

Potentiometric Sensing

2018

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“…As the difference between the models is relatively small and the experimental scans include the flat background substrate, the planar model is used herein when describing the Gram-negative bacterial scans. Note that although COMSOL Multiphysics can, in principle, be used for three-dimensional simulations, ,, the accuracy can be compromised and/or simulations become computationally expensive for complex problems, such as in this case, where there is an interplay of ion migration and electroosmotic fluid flow, and there is a need to consider charged interfaces. We thus retained a 2D model to assess the effect of a curved interface.…”

Section: Resultsmentioning

confidence: 99%

Scanning Ion Conductance Microscopy Reveals Differences in the Ionic Environments of Gram-Positive and Negative Bacteria

et al. 2020

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This paper reports on the use of scanning ion conductance microscopy (SICM) to locally map the ionic properties and charge environment of two live bacterial strains: the Gram-negative Escherichia coli and the Gram-positive Bacillus subtilis. SICM results find heterogeneities across the bacterial surface and significant differences among the Gram-positive and Gram-negative bacteria. The bioelectrical environment of the B. subtilis was found to be considerably more negatively charged compared to E. coli. SICM measurements, fitted to a simplified finite element method (FEM) model, revealed surface charge values of −80 to −140 mC m −2 for the Gram-negative E. coli. The Gram-positive B. subtilis show a much higher conductivity around the cell wall, and surface charge values between −350 and −450 mC m −2 were found using the same simplified model. SICM was also able to detect regions of high negative charge near B. subtilis, not detected in the topographical SICM response and attributed to the extracellular polymeric substance. To further explore how the B. subtilis cell wall structure can influence the SICM current response, a more comprehensive FEM model, accounting for the physical properties of the Gram-positive cell wall, was developed. The new model provides a more realistic description of the cell wall and allows investigation of the relation between its key properties and SICM currents, building foundations to further investigate and improve understanding of the Gram-positive cellular microenvironment.

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“…As the difference between the models is relatively small, and the experimental scans include the flat background substrate, the planar model is used herein when describing the gram-negative bacterial scans. Note that although COMSOL Multiphysics can, in principle, be used for 3-dimensional simulations, 21,41,42 the accuracy can be compromised and/or simulations become computationally expensive for complex problems, such as here, where there is an interplay of ion migration and electroosmotic fluid flow, and the need to consider charged interfaces. We thus retained a 2D model to assess the effect of a curved interface.…”

Section: Resultsmentioning

confidence: 99%

Scanning ion conductance microscopy reveals differences in the ionic environments of gram positive and negative bacteria

Cremin

Jones

Teahan

et al. 2020

Preprint

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This paper reports on the use of scanning ion conductance microscopy (SICM) to locally map the ionic properties and charge environment of two live bacterial strains: the gramnegative Escherichia coli and the gram-positive Bacillus subtilis. SICM results find heterogeneities across the bacterial surface, and significant differences among the grampositive and -negative bacteria. The bioelectrical environment of the B. subtilis was found to be considerably more negatively charged compared to E. coli. SICM measurements, fitted to a simplified finite element method (FEM) model, revealed surface charge values of −80 to −140 mC m−2 for the gram-negative E. coli. The gram-positive B. subtilis show a much higher conductivity around the cell wall, and surface charge values between −350 and −450 mC m−2 were found using the same simplified model. SICM was also able to detect regions of high negative charge near B. subtilis, not detected in the topographical SICM response and attributed to extracellular polymeric substance. To further explore how the B. subtilis cell wall structure can influence the SICM current response, a more comprehensive FEM model, accounting for the physical properties of the gram-positive cell wall, was developed. The new model provides a more realistic description of the cell wall and allowed investigation of the relation between its key properties and SICM currents, building foundations to further investigate and improve understanding of the gram-positive cellular microenvironment.Abstract Figure

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Novel dual Pt-Pt/IrO ultramicroelectrode for pH imaging using SECM in both potentiometric and amperometric modes

Cited by 35 publications

References 23 publications

Potentiometric Sensing

Potentiometric Sensing

Scanning Ion Conductance Microscopy Reveals Differences in the Ionic Environments of Gram-Positive and Negative Bacteria

Scanning ion conductance microscopy reveals differences in the ionic environments of gram positive and negative bacteria

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