Retrospective chemical analysis of tree rings by means of the scanning electrochemical microscopy with shear force feedback

Garay, Maria Florencia; Ufheil, Joachim; Borgwarth, K.; Heınze, Jürgen

doi:10.1039/b402458c

Cited by 17 publications

(3 citation statements)

References 28 publications

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“…SECM allows the monitoring of topography and reactivity of biological samples, such as cancer cells . Since its first application to biological samples in the 1990s, a variety of living samples was analyzed, including bacteria (e.g., refs and ), plant (e.g., refs and ) and human cell tissue (e.g., ref ), or cultures (e.g., refs and ). A live cell’s redox environment can be followed noninvasively and even on the single cell level .…”

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confidence: 99%

High-Speed Scanning Electrochemical Microscopy Method for Substrate Kinetic Determination: Application to Live Cell Imaging in Human Cancer

2015

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Scanning electrochemical microscopy (SECM) is increasingly applied to study and image live cells. Quantitative analyses of biological systems, however, still remain challenging. In the presented study, single human adenocarcinoma cervical cancer cells are electrochemically investigated by means of SECM. The target cell's electrochemical response is observed over time under the influence of green tea catechins (GTC), which are suggested to offer chemopreventive and therapeutic effects on cancer. The electrochemical response of living target cells is measured experimentally and quantified in an apparent heterogeneous rate constant by using a numerical model, based on forced convection during high speed SECM imaging. The beneficial effect of GTC on cancer cells could be confirmed by SECM, and the presented study shows an alternative approach toward unraveling the mechanisms involved during inhibition of carcinogenesis.

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High-Speed Scanning Electrochemical Microscopy Method for Substrate Kinetic Determination: Application to Live Cell Imaging in Human Cancer

2015

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“…The above inherent shortcomings can be overcome by constant-distance SECM (Figure b), where the electrode-to-cell distance is maintained constant during the scan by utilizing the distance-dependent feedback signal . Shear force based distance control has been successfully introduced in this SECM mode, where the probe was attached to a piezoelectric tuning fork − or a piezo dither. − SECM was also combined with atomic force microscope (AFM) . Sophisticated instrumentation and probe fabrication are required.…”

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confidence: 99%

Deconvoluting Topography and Spatial Physiological Activity of Live Macrophage Cells by Scanning Electrochemical Microscopy in Constant-Distance Mode

2010

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Detection of reactive oxygen species (ROS) released from live macrophage cells (RAW264.7) without any addition of external redox mediators using constant-height and constant-distance mode scanning electrochemical microscopy (SECM) was presented in this Letter. The successful separation of the ROS profile from the topography of cells in the physiological condition was demonstrated by recording the amperometric current and probing position in the z-direction along with lateral coordinates at each pixel where an alternating current (AC) was kept constant. It was discovered that the nucleus region of the cell releases more ROS than other organelle regions and the height of the cell is approximately 4.8 μm. To our best knowledge, this work reports the first spatially monitored ROS release without the influence of cell morphology using SECM.

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“…A few techniques have been developed that make use of an alternative distance-dependent signal, the most prominent of which uses shear force feedback. ,− In this adaptation of a distance control technique from near-field scanning optical microscopy, the SECM tip is driven to its resonant frequency by a piezoelectric oscillator. As the tip approaches a surface, the damping of the tip frequency by the shear force of the solution is detected with a second piezoelectric device or by the deflection of a laser beam.…”

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confidence: 99%

Scanning Electrochemical Microscopy of Model Neurons: Constant Distance Imaging

et al. 2005

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Undifferentiated and differentiated PC12 cells were imaged with the constant-distance mode of scanning electrochemical microscopy (SECM) using carbon ring and carbon fiber tips. Two types of feedback signals were used for distance control: the electrolysis current of a mediator (constant-current mode) and the impedance measured by the SECM tip (constant-impedance mode). The highest resolution was achieved using carbon ring electrodes with the constant-current mode. However, the constant-impedance mode has the important advantages that topography and faradaic current can be measured simultaneously, and because no mediator is required, the imaging can take place directly in the cell growth media. It was found that vesicular release events do not measurably alter the impedance, but the depolarizing solution, 105 mM K+, produces a dramatic impedance change such that constant-distance imaging cannot be performed during application of the stimulus. However, by operating the tip in the constant-height mode, cell morphology (via a change in impedance) and vesicular release could be detected simultaneously while moving the tip across the cell. This work represents a significant improvement over previous SECM imaging of model neurons, and it demonstrates that the combination of amperometry and constant-impedance SECM has the potential to be a powerful tool for investigating the spatial distribution of neurotransmitter release in vitro.

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Retrospective chemical analysis of tree rings by means of the scanning electrochemical microscopy with shear force feedback

Cited by 17 publications

References 28 publications

High-Speed Scanning Electrochemical Microscopy Method for Substrate Kinetic Determination: Application to Live Cell Imaging in Human Cancer

High-Speed Scanning Electrochemical Microscopy Method for Substrate Kinetic Determination: Application to Live Cell Imaging in Human Cancer

Deconvoluting Topography and Spatial Physiological Activity of Live Macrophage Cells by Scanning Electrochemical Microscopy in Constant-Distance Mode

Scanning Electrochemical Microscopy of Model Neurons: Constant Distance Imaging

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