Application of scanning electrochemical microscopy to biological samples

Area of Science:

• Electrochemistry
• Microscopy
• Surface Science

Background:

• The scanning electrochemical microscope (SECM) offers a powerful approach for analyzing biological surfaces at the micrometer scale.
• Feedback mode SECM is particularly useful for obtaining topographic and functional information from diverse substrates.

Purpose of the Study:

• To demonstrate the utility of SECM in feedback mode for high-resolution topographic imaging of biological samples.
• To showcase the capability of SECM to map spatially resolved electrochemical activity on plant leaf surfaces.

Main Methods:

• Utilized SECM in feedback mode with an ultramicroelectrode tip.
• Performed two-dimensional scans over biological substrates (grass and Ligustrum sinensis leaves) immersed in aqueous solution.
• Recorded electrolytic current as a function of tip position to correlate with substrate topography and electrochemical activity.

Main Results:

• Successfully obtained micrometer-level topographic maps of leaf surfaces, revealing structures like stomata.
• Demonstrated SECM's ability to map oxygen production sites on an elodea leaf surface under irradiation by monitoring oxygen reduction at the tip.
• Showcased the technique's applicability to both conductive and insulating biological substrates.

Conclusions:

• SECM in feedback mode is a versatile tool for topographic and functional imaging of biological surfaces.
• The technique can provide insights into the distribution of electrochemical reaction sites, such as photosynthetic activity, on biological samples.
• SECM opens avenues for detailed surface analysis in plant biology and other life science fields.