Alternating current scanning electrochemical microscopy with simultaneous fast-scan cyclic voltammetry

Area of Science:

• Electrochemistry
• Scanning Probe Microscopy
• Chemical Imaging

Background:

• Simultaneous chemical and topographical imaging is crucial for understanding complex biological and material systems.
• Existing techniques often require multiple probes or lack the resolution for detailed cellular analysis.

Purpose of the Study:

• To develop and validate a combined fast-scan cyclic voltammetry (FSCV) and alternating current scanning electrochemical microscopy (AC-SECM) technique.
• To enable simultaneous measurement of impedance and faradaic current using a single probe.
• To demonstrate the technique's utility in imaging living cell cultures.

Main Methods:

• Integration of a high-frequency, low-amplitude sine wave with FSCV waveforms (10-1000 V s(-1)).
• Utilized lock-in amplifier and analog circuit for AC signal amplitude measurement.
• Employed a single carbon fiber probe for simultaneous electrochemical and topographical data acquisition.

Main Results:

• The combined FSCV and AC-SECM technique provided simultaneous chemical and topographical information.
• The added AC signal exhibited negligible effects on the voltammetric measurements at a carbon fiber electrode.
• Successfully imaged cellular respiration and topography in living cell cultures without redox mediators.

Conclusions:

• The developed FSCV and AC-SECM combination offers a powerful tool for multidimensional chemical and topographical imaging.
• This technique eliminates the need for redox mediators, simplifying sample preparation and analysis.
• The approach holds significant promise for advanced imaging applications in biological and material sciences.