Label-Free Imaging of Cell Apoptosis by a Light-Addressable Electrochemical Sensor

Area of Science:

• Biomedical Engineering
• Electrochemistry
• Cancer Research

Background:

• Label-free visualization of cancer cell apoptosis is crucial for developing effective cancer therapies.
• Current methods may lack the sensitivity or specificity to capture the heterogeneity of apoptosis.
• Noninvasive imaging techniques are needed for real-time monitoring of cellular responses to treatment.

Purpose of the Study:

• To develop a noninvasive, label-free imaging method for visualizing drug-induced cancer cell apoptosis.
• To investigate the dynamic changes in electrochemical signals during apoptosis.
• To explore the heterogeneity of apoptosis at the single-cell level.

Main Methods:

• Utilized a light-addressable electrochemical sensor (LAES) for imaging.
• Monitored dynamic AC photocurrent changes in MCF-7 breast adenocarcinoma cells treated with tamoxifen.
• Analyzed changes in ζ potential and Faradaic impedance to understand photocurrent variations.

Main Results:

• Observed an increase in AC photocurrent on apoptotic MCF-7 cells.
• Demonstrated heterogeneous degrees of apoptosis among individual cells.
• Correlated photocurrent increase with increased cell membrane permeability and cell-substrate gap widening during apoptosis.

Conclusions:

• The LAES method provides a novel approach for label-free visualization of apoptosis heterogeneity.
• This technique has significant potential for drug screening and evaluating drug efficacy in cancer therapy.
• Understanding apoptosis heterogeneity is key for personalized cancer treatment strategies.