Label free aptasensor for ochratoxin A detection using polythiophene-3-carboxylic acid

Area of Science:

• Electrochemistry
• Biosensors
• Analytical Chemistry

Background:

• Ochratoxin A (OTA) is a common food contaminant with significant health risks.
• Accurate and sensitive detection methods for OTA are crucial for food safety.
• Electrochemical aptasensors offer a promising platform for rapid and selective toxin detection.

Purpose of the Study:

• To develop and optimize an electrochemical aptasensor for the direct detection of ochratoxin A (OTA).
• To evaluate different aptamer immobilization strategies using conductive polymers.
• To assess the performance of the developed aptasensor in complex matrices like coffee.

Main Methods:

• Development of an electrochemical aptasensor using OTA aptamers immobilized on polythiophene-3-carboxylic acid (PT3C).
• Screen-printed carbon electrodes (SPCE) were utilized as the transducer.
• Electrochemical impedance spectroscopy (EIS) was employed for OTA quantification.

Main Results:

• The PT3C-based aptasensor demonstrated high sensitivity for OTA detection.
• A wide dynamic range (0.125–2.5 ng/mL) with a low limit of detection (0.125 ng/mL) was achieved.
• The aptasensor showed good reproducibility (RSD% of 3.68) and effectiveness in real coffee samples with recovery rates of 88–89%.

Conclusions:

• The developed electrochemical aptasensor provides a sensitive, reproducible, and effective method for OTA detection.
• Polythiophene-3-carboxylic acid is a suitable material for aptamer immobilization in electrochemical sensing applications.
• The aptasensor shows potential for routine monitoring of OTA in food products.