Scanning electrochemical microscopy. 24. Enzyme ultramicroelectrodes for the measurement of hydrogen peroxide at surfaces

Horrocks, Benjamin R.; Schmidtke, David W.; Heller, Adam; Bard, Allen J.

doi:10.1021/ac00072a013

Cited by 198 publications

(163 citation statements)

References 17 publications

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“…Bard and co-workers [69] have used UMEs with tips modi®ed with polymer-entrapped horseradish peroxidase as biosensors for the detection of hydrogen peroxide produced during the enzymatic oxidation of glucose by immobilised GO. The probes had a limited pH range (ca.…”

Section: Redox Processes On Biological Surfacesmentioning

confidence: 99%

Scanning electrochemical microscopy: beyond the solid/liquid interface

Barker

Gonsalves

Macpherson

et al. 1999

Analytica Chimica Acta

145

107

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Section: Redox Processes On Biological Surfacesmentioning

confidence: 99%

Scanning electrochemical microscopy: beyond the solid/liquid interface

Barker

Gonsalves

Macpherson

et al. 1999

Analytica Chimica Acta

145

107

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“…5 Enzymes catalyze with high specificity chemical reactions in biological systems according to Equation 1: (1) Enzymes have been successfully employed in the miniaturization of sensor designs, including one of the most important sensors for the health industry that emerged decades ago: the glucose sensor which is based on glucose oxidase (GOx), whether it is intended for in vivo monitoring of glucose levels, 6 or for a diabetic's regular glucose meter for use at home. Besides GOx, there have been numerous other enzymes used for the development of miniaturized amperometric sensors, such as sarcosine oxidase, 7 galactose oxidase, 7 hexokinase, 8 choline oxidase, 7 lactate oxidase (LOx), 9 alcohol oxidase, 7 horseradish peroxidase, 10 cholesterol oxidase, 11,12 etc.…”

Section: Introductionmentioning

confidence: 99%

“…Horrocks et al 10 have used an enzyme (horseradish peroxidase) UME in conjunction with the scanning electrochemical microscopy (SECM) for the measurement of H 2 O 2 at surfaces. They do not present any amperometric approach curves (ACs), but rather conductance-distance curves.…”

Section: Introductionmentioning

confidence: 99%

Glucose and Lactate Biosensors for Scanning Electrochemical Microscopy Imaging of Single Live Cells

et al. 2008

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We have developed glucose and lactate ultramicroelectrode (UME) biosensors based on glucose oxidase and lactate oxidase (with enzymes immobilized onto Pt UMEs by either electropolymerization or casting) for scanning electrochemical microscopy (SECM), and have determined their sensitivity to glucose and lactate, respectively. The results of our evaluations reveal different advantages for sensors constructed by each method: improved sensitivity and shorter manufacturing time for hand-casting, and increased reproducibility for electropolymerization. We have acquired amperometric approach curves (ACs) for each type of manufactured biosensor UME, and these ACs can be used as a means of positioning the UME above a substrate at a known distance. We have used the glucose biosensor UMEs to record profiles of glucose uptake above individual fibroblasts. Likewise, we have employed the lactate biosensor UMEs for recording the lactate production above single cancer cells with the SECM. We also show that oxygen respiration profiles for single cancer cells do not mimic cell topography, but are rather more convoluted, with a higher respiration activity observed at the points where the cell touches the Petri dish. These UME biosensors, along with the application of others already described in the literature, could prove to be powerful tools for mapping metabolic analytes, such as glucose, lactate and oxygen, in single cancer cells.

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“…SECM has the unique ability to set the exact distance from a sensing tip [an ultramicroelectrode (UME) of size ∼10 to 25 μm diameter] to a substrate through a feedback approach curve (11) (tip current, i T , vs. distance above substrate, d) and thus is able to measure the local concentration over a biofilm. Several studies concerned with the electrochemical measurement of hydrogen peroxide concentration have been reported (12)(13)(14)(15)(16)(17), but none dealt with spatial mapping adjacent to a biofilm surface. In addition, SECM has the ability to scan over a substrate in the x-y direction and thus is able to record a unique spatial concentration profile over the surface.…”

mentioning

confidence: 99%

Real-time mapping of a hydrogen peroxide concentration profile across a polymicrobial bacterial biofilm using scanning electrochemical microscopy

Liu

Ramsey

Chen

et al. 2011

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

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144

118

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Quantitative detection of hydrogen peroxide in solution above a Streptococcus gordonii (Sg) bacterial biofilm was studied in real time by scanning electrochemical microscopy (SECM). The concentration of hydrogen peroxide was determined to be 0.7 mM to 1.6 mM in the presence of 10 mM glucose over a period of 2 to 8 h. The hydrogen peroxide production measured was higher near the biofilm surface in comparison to Sg grown planktonically. Differential hydrogen peroxide production was observed both by fluorometric as well as by SECM measurements. The interaction between two different species in a bacterial biofilm of Sg and Aggregatibacter actinomycetemcomitans (Aa) in terms of hydrogen peroxide production was also studied by SECM. One-directional y-scan SECM measurements showed the unique spatial mapping of hydrogen peroxide concentration across a mixed species biofilm and revealed that hydrogen peroxide concentration varies greatly dependent upon local species composition.real-time (detection) | metabolite efflux | local concentration | oral flora | Au UME S treptococcus gordonii (Sg) is a member of the viridans group streptococci-Gram-positive oral microbes that are known to ferment sugars into lactic acid and produce hydrogen peroxide in the presence of oxygen (1). The presence of these beneficial oral streptococci has been shown to improve oral health, by either competition with pathogens for nutrients in the oral cavity or by the production of inhibitory concentrations of hydrogen peroxide. Populations of viridans group streptococci negatively correlate with the presence of many notable oral pathogens (2, 3). However, recent work has demonstrated that in vitro Sg can grow in coculture with the opportunistic oral pathogen Aggregatibacter actinomycetemcomitans (Aa) (4). In co-culture Aa preferentially utilizes Sg-produced lactic acid (5) and detoxifies Sg-produced hydrogen peroxide using the KatA enzyme (6). Recent work has demonstrated that hydrogen peroxide induces katA expression as well as apiA, which encodes an immunoprotective factor that renders Aa more resistant to killing by host innate immunity (5). These studies demonstrated induction of gene expression in mixed species biofilms by Sg-produced hydrogen peroxide. Because hydrogen peroxide is rapidly degraded by catalase and can also react with other biological materials, we sought to quantify local hydrogen peroxide concentrations in real time to be utilized for future polymicrobial experiments between Sg, Aa, and other oral bacteria.Previous measurements of hydrogen peroxide have been performed using fluorescence, spectroscopy and other methods (1, 7-10). However, current techniques lack the ability to quantify local hydrogen peroxide concentrations at the surface of a biofilm. In this study, scanning electrochemical microscopy (SECM) was used to address this problem. SECM has the unique ability to set the exact distance from a sensing tip [an ultramicroelectrode (UME) of size ∼10 to 25 μm diameter] to a substrate through a feedback approach curve (11)...

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Scanning electrochemical microscopy. 24. Enzyme ultramicroelectrodes for the measurement of hydrogen peroxide at surfaces

Cited by 198 publications

References 17 publications

Scanning electrochemical microscopy: beyond the solid/liquid interface

Scanning electrochemical microscopy: beyond the solid/liquid interface

Glucose and Lactate Biosensors for Scanning Electrochemical Microscopy Imaging of Single Live Cells

Real-time mapping of a hydrogen peroxide concentration profile across a polymicrobial bacterial biofilm using scanning electrochemical microscopy

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