On-Chip Electrochemical Detection of Cholera Using a Polypyrrole-Functionalized Dendritic Gold Sensor

Area of Science:

• Electrochemistry
• Biosensors
• Nanotechnology

Background:

• Rapid diagnosis of infectious disease outbreaks is crucial to prevent epidemics.
• Point-of-care (POC) cholera diagnostics require high sensitivity, specificity, portability, and simplicity.
• Existing methods may lack the necessary performance for field deployment.

Purpose of the Study:

• To develop an on-chip electrochemical immunosensor for detecting cholera toxin subunit B (CTX).
• To utilize a dendritic gold architecture biofunctionalized with poly(2-cyanoethyl)pyrrole (PCEPy) for enhanced sensitivity.
• To evaluate the sensor's performance for rapid, portable cholera diagnosis.

Main Methods:

• Fabrication of an electrochemical immunosensor on a dendritic gold architecture.
• Biofunctionalization of the dendritic surface with PCEPy.
• Performance of an electrochemical enzyme-linked immunosorbant assay (ELISA) for CTX detection.
• Comparison with a planar gold electrode and optical ELISA.

Main Results:

• The dendritic gold electrode exhibited an ~18x greater surface area than a planar electrode.
• The PCEPy-modified sensor achieved a detection limit of 1 ng mL^-1 for CTX.
• This represents a 100-fold improvement over the planar gold electrode (100 ng mL^-1).
• The on-chip sensor performance matched that of a standard optical ELISA.

Conclusions:

• Biofunctionalized gold dendrites provide a highly sensitive platform for on-chip electrochemical detection.
• The developed immunosensor meets key requirements for POC diagnostics, including portability and simplified readout.
• This technology shows significant promise for the rapid field diagnosis of cholera outbreaks.