Electrochemical detection of epidermal growth factor receptors on a single living cell surface by scanning...

Area of Science:

• Biophysical Chemistry
• Cell Biology
• Analytical Chemistry

Background:

• Epidermal growth factor receptor (EGFR) is a key membrane protein implicated in various cancers.
• EGFR signaling influences cell proliferation, differentiation, apoptosis, and migration.
• Accurate quantification of EGFR on single cells is vital for cancer research.

Purpose of the Study:

• To develop and validate a method for quantifying EGFR expression on single living mammalian cells using SECM.
• To optimize antibody labeling for EGFR detection.
• To compare EGFR expression levels across different cell types.

Main Methods:

• Scanning electrochemical microscopy (SECM) was employed to image membrane proteins on single living cells.
• EGFR was labeled with alkaline phosphatase (ALP) using an antibody.
• The oxidation current of p-aminophenol (PAP), catalyzed by ALP, was monitored to estimate EGFR density.
• Faradaic current detection allowed for quantitative in situ measurements on living cells.

Main Results:

• The study successfully optimized antibody labeling concentrations for EGFR detection.
• Distinct differences in EGFR expression levels were observed among three different cell types.
• SECM measurements demonstrated compatibility and agreement with flow cytometry results.
• SECM provides single-cell level information on EGFR expression at the cell membrane.

Conclusions:

• SECM is a powerful technique for quantifying EGFR on single living cells without detachment.
• This method offers advantages for optimizing assays and provides detailed spatial information.
• SECM measurements correlate well with established techniques like flow cytometry, validating its utility in cancer research.