Biosensor incorporating cell barrier architectures for detecting Staphylococcus aureus alpha toxin.

Area of Science:

• Microbiology
• Biomedical Engineering
• Cell Biology

Background:

• Staphylococcus aureus alpha toxin is a key virulence factor contributing to pathogenicity.
• Alpha toxin disrupts endothelial cell monolayer integrity, increasing permeability via intercellular gap formation.

Purpose of the Study:

• To develop and validate a whole-cell-based biosensor for quantifying alpha toxin.
• To investigate the correlation between biosensor response and toxin-induced endothelial cell damage.

Main Methods:

• A biosensor was constructed using human umbilical vein endothelial cells (HUVECs) on a potassium ion-selective electrode.
• The biosensor detected alpha toxin by measuring changes in cell monolayer permeability and potassium ion flux.
• Silver nitrate staining was used to visualize and quantify intercellular gaps and assess HUVEC morphology.

Main Results:

• The biosensor demonstrated an increased response with increasing alpha toxin concentrations.
• A detection limit of 0.1 ng/ml for alpha toxin was achieved.
• A strong positive correlation was found between biosensor response and the area of intercellular gaps.

Conclusions:

• The developed HUVEC-based biosensor is effective for sensitive detection of alpha toxin.
• The biosensor's response correlates with the extent of endothelial cell damage, offering a functional measure of toxin activity.