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

2011 ◽  
Vol 108 (7) ◽  
pp. 2668-2673 ◽  
Author(s):  
X. Liu ◽  
M. M. Ramsey ◽  
X. Chen ◽  
D. Koley ◽  
M. Whiteley ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Real Time ◽  
Concentration Profile ◽  
Scanning Electrochemical Microscopy ◽  
Bacterial Biofilm ◽  
Electrochemical Microscopy

scholarly journals Micron Scale Spatial Measurement of the O2 Gradient Surrounding a Bacterial Biofilm in Real Time

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Alexander D. Klementiev ◽  
Zhaoyu Jin ◽  
Marvin Whiteley
Keyword(s):  
Real Time ◽  
Critical Role ◽  
Scanning Electrochemical Microscopy ◽  
Antimicrobial Treatment ◽  
Bacterial Biofilm ◽  
Content Type ◽  
Hypoxic Zone ◽  
Life On Earth ◽  
And Behavior ◽  
Electrochemical Microscopy

ABSTRACT Bacteria alter their local chemical environment through both consumption and the production of a variety of molecules, ultimately shaping the local ecology. Molecular oxygen (O2) is a key metabolite that affects the physiology and behavior of virtually all bacteria, and its consumption often results in O2 gradients within sessile bacterial communities (biofilms). O2 plays a critical role in several bacterial phenotypes, including antibiotic tolerance; however, our understanding of O2 levels within and surrounding biofilms has been hampered by the difficulties in measuring O2 levels in real-time for extended durations and at the micron scale. Here, we developed electrochemical methodology based on scanning electrochemical microscopy to quantify the O2 gradients present above a Pseudomonas aeruginosa biofilm. These results reveal that a biofilm produces a hypoxic zone that extends hundreds of microns from the biofilm surface within minutes and that the biofilm consumes O2 at a maximum rate. Treating the biofilm with levels of the antibiotic ciprofloxacin that kill 99% of the bacteria did not affect the O2 gradient, indicating that the biofilm is highly resilient to antimicrobial treatment in regard to O2 consumption. IMPORTANCE O2 is a fundamental environmental metabolite that affects all life on earth. While toxic to many microbes and obligately required by others, those that have appropriate physiological responses survive and can even benefit from various levels of O2, particularly in biofilm communities. Although most studies have focused on measuring O2 within biofilms, little is known about O2 gradients surrounding biofilms. Here, we developed electrochemical methodology based on scanning electrochemical microscopy to measure the O2 gradients surrounding biofilms in real time on the micron scale. Our results reveal that P. aeruginosa biofilms produce a hypoxic zone that can extend hundreds of microns from the biofilm surface and that this gradient remains even after the addition of antibiotic concentrations that eradicated 99% of viable cells. Our results provide a high resolution of the O2 gradients produced by P. aeruginosa biofilms and reveal sustained O2 consumption in the presence of antibiotics.

scholarly journals Ultramicrosensors based on transition metal hexacyanoferrates for scanning electrochemical microscopy

2013 ◽  
Vol 4 ◽  
pp. 649-654 ◽  
Author(s):  
Maria A Komkova ◽  
Angelika Holzinger ◽  
Andreas Hartmann ◽  
Alexei R Khokhlov ◽  
Christine Kranz ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Detection Limit ◽  
Transition Metal ◽  
Prussian Blue ◽  
Electrochemical Deposition ◽  
Mixed Layer ◽  
Scanning Electrochemical Microscopy ◽  
The Stability ◽  
Mixed Layers ◽  
Electrochemical Microscopy

We report here a way for improving the stability of ultramicroelectrodes (UME) based on hexacyanoferrate-modified metals for the detection of hydrogen peroxide. The most stable sensors were obtained by electrochemical deposition of six layers of hexacyanoferrates (HCF), more specifically, an alternating pattern of three layers of Prussian Blue and three layers of Ni–HCF. The microelectrodes modified with mixed layers were continuously monitored in 1 mM hydrogen peroxide and proved to be stable for more than 5 h under these conditions. The mixed layer microelectrodes exhibited a stability which is five times as high as the stability of conventional Prussian Blue-modified UMEs. The sensitivity of the mixed layer sensor was 0.32 A·M−1·cm−2, and the detection limit was 10 µM. The mixed layer-based UMEs were used as sensors in scanning electrochemical microscopy (SECM) experiments for imaging of hydrogen peroxide evolution.

scholarly journals Nanoscale Intelligent Imaging Based on Real-Time Analysis of Approach Curve by Scanning Electrochemical Microscopy

2019 ◽  
Vol 91 (15) ◽  
pp. 10227-10235
Author(s):  
Ryan J. Balla ◽  
Dylan T. Jantz ◽  
Niraja Kurapati ◽  
Ran Chen ◽  
Kevin C. Leonard ◽  
...  
Keyword(s):  
Real Time ◽  
Scanning Electrochemical Microscopy ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Electrochemical Microscopy

Scanning Electrochemical Microscopy of Model Neurons:  Imaging and Real-Time Detection of Morphological Changes

2003 ◽  
Vol 75 (3) ◽  
pp. 563-571 ◽  
Author(s):  
Johanna M. Liebetrau ◽  
Heather M. Miller ◽  
John E. Baur ◽  
Sara A. Takacs ◽  
Vipavee Anupunpisit ◽  
...  
Keyword(s):  
Real Time ◽  
Morphological Changes ◽  
Scanning Electrochemical Microscopy ◽  
Real Time Detection ◽  
Electrochemical Microscopy

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

1993 ◽  
Vol 65 (24) ◽  
pp. 3605-3614 ◽  
Author(s):  
Benjamin R. Horrocks ◽  
David. Schmidtke ◽  
Adam. Heller ◽  
Allen J. Bard
Keyword(s):  
Hydrogen Peroxide ◽  
Scanning Electrochemical Microscopy ◽  
Electrochemical Microscopy
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