Photocurrent Polarity-Switchable Imaging of Single Living Cells by Light-Addressable Electrochemical Sensor

Area of Science:

• Electrochemistry
• Materials Science
• Biotechnology

Background:

• Light-addressable electrochemical sensing (LAES) offers label-free and probe-free advantages for single-cell imaging.
• Conventional LAES systems are typically limited to single-polarity photocurrent operation.

Purpose of the Study:

• To develop a photocurrent polarity-switchable LAES for enhanced living cell imaging.
• To utilize a single-phase bismuth ferrite (BiFeO3) thin film as a photoelectrode capable of exhibiting both p-type and n-type photocurrent behavior.

Main Methods:

• Fabrication of a BiFeO3 thin film photoelectrode.
• Implementation of LAES with switchable photocurrent polarity (anodic and cathodic modes).
• Imaging of MCF-7 cells under different conditions, including post-trypsin treatment, to observe dynamic photocurrent changes.

Main Results:

• The BiFeO3 photoelectrode demonstrated switchable p-type and n-type photocurrent behavior by adjusting external bias voltage.
• LAES imaging revealed decreases in photocurrent due to cell adhesion and increases upon cell-substrate junction weakening after trypsin treatment.
• The study successfully achieved LAES cell imaging in a p-type mode for the first time, showcasing heterogeneous dynamic changes.

Conclusions:

• The developed photocurrent polarity-switchable LAES overcomes limitations of single-polarity systems.
• This technology significantly expands the application scope of LAES for single-cell visualization and analysis.
• The findings provide valuable insights into cellular behavior and function through advanced imaging techniques.