Investigation of concentration profiles inside operating biocatalytic sensors with scanning electrochemical microscopy (SECM)

Csóka, Balázs; Kovács, Barna; Nagy, Géza

doi:10.1016/s0956-5663(02)00167-7

Cited by 39 publications

(14 citation statements)

References 19 publications

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“…4 also confirm experimental observations that an optimal size of the entrapment domain exists [24,45,46]. The existence of a Z corresponding to a maximum electrode effectiveness K′ is evident in Fig.…”

Section: Transition Between Regimes-supporting

confidence: 84%

Theory of polymer entrapped enzyme ultramicroelectrodes: Fundamentals

Kottke

Kranz

Kwon

et al. 2008

Journal of Electroanalytical Chemistry

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We have developed a theoretical description of the amperometric response of ultramicroelectrode (UME) biosensors formed via enzyme entrapment. Our model allows for multiple enzymes and cosubstrates, and results in a closed-form analytical expression for the steady-state current response of the disk ultramicroelectrode. It captures the effects of enzyme-entrapment domain size, species transport properties (which can be different in the polymer and surrounding electrolyte), enzyme kinetics, and axisymmetric diffusion. Assumptions inherent in the derivation are carefully explained, as are the resulting limits on the applicability of the results. The ability to theoretically predict the response of enzyme entrapped UMEs should enable improved design, operation, and data interpretation for this important class of biosensors.

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Section: Transition Between Regimes-supporting

confidence: 84%

Theory of polymer entrapped enzyme ultramicroelectrodes: Fundamentals

Kottke

Kranz

Kwon

et al. 2008

Journal of Electroanalytical Chemistry

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“…Linescans were performed by scanning back and forth above the center of the target with the same resolution, and tip to substrate distance. A home‐made SECM was used with a custom software 16 to allow the high scan rate.…”

Section: Methodsmentioning

confidence: 99%

Deconvolution in Potentiometric SECM

Nagy

2015

Electroanalysis

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One of the main limitations of potentiometric scanning electrochemical microscopy (SECM) is the large RC time constant, and therefore long response time of the cell. A relatively long equilibration interval has to be allowed before sampling at each data acquisition point to reach equilibrium potential, and avoid image distortion. In this paper, we present a method to get high‐quality, low distortion images, without increasing scan time. The convolution function causing the distortion can be expressed from the response function of the potentiometric cell. A model system was studied with high scan rate, then the image was deconvoluted using the inverse of the potentiometric response function to calculate the equilibrium potential for each data acquisition point from the respective observed values.

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“…The carbon microelectrode used in the SECM experiments was prepared according to the procedure described before 29 . First, a borosilicate capillary was rinsed with acetone and double distilled water.…”

Section: Electrochemical Characterizationmentioning

confidence: 99%

In Situ Investigation of the Cytotoxic and Interfacial Characteristics of Titanium When Galvanically Coupled with Magnesium Using Scanning Electrochemical Microscopy

Asserghine

Ashrafi

Mukherjee

et al. 2021

ACS Appl. Mater. Interfaces

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Recently, the cytotoxic properties of galvanically coupled Mg-Ti particles have been shown to different cells, although this cytotoxic effect has been attributed mainly to Mg due to its tendency to undergo activation when coupled with Ti forming a galvanic cell consisting of an anode (Mg) and a cathode (Ti). However, the role of the Ti cathode has been ignored in explaining the cytotoxic effect of Mg-Ti particles due to its high resistance to corrosion. In this work, the role of titanium (Ti) in the cytotoxic mechanism of galvanically coupled Mg-Ti particles was examined. A model galvanic cell was prepared to simulate the Mg-Ti particles.The electrochemical reactivity of the Ti sample and the pH change above it due to galvanic coupling with Mg were investigated using scanning electrochemical microscopy (SECM). It was observed that the Ti surface changed from passive to electrochemically active when coupled with Mg. Furthermore, after only 15 min galvanic coupling with Mg, the pH in the electrolyte volume adjacent to the Ti surface increased to an alkaline pH value. The effects of the galvanic coupling of Ti and Mg, as well as of the alkaline pH environment, on the viability of Hs27 fibroblast cells were investigated. It was shown that the viability of Hs27 cells significantly diminished when Mg and Ti were galvanically coupled compared to when the two metals were electrically disconnected. Next, the generation of reactive oxygen species (ROS) increased when the Ti and Mg were galvanically coupled. Thus, although Ti usually exhibited high corrosion resistance when exposed to physiological environments, an electrochemically active surface was observed when galvanically coupled with Mg, and this surface may participate in electron transfer reactions with chemical species in the neighboring environment; this participation resulted in the increased pH values above its surface and enhanced generation of ROS. These features contributed to the development of cytotoxic effects by galvanically coupled Mg-Ti particles.

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Investigation of concentration profiles inside operating biocatalytic sensors with scanning electrochemical microscopy (SECM)

Cited by 39 publications

References 19 publications

Theory of polymer entrapped enzyme ultramicroelectrodes: Fundamentals

Theory of polymer entrapped enzyme ultramicroelectrodes: Fundamentals

Deconvolution in Potentiometric SECM

In Situ Investigation of the Cytotoxic and Interfacial Characteristics of Titanium When Galvanically Coupled with Magnesium Using Scanning Electrochemical Microscopy

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