Electrochemical Biosensor for Polycyclic Organic Compounds Screening Based on a Methylene Blue-incorporated DNA...

Area of Science:

• Electrochemistry
• Biosensor Technology
• Analytical Chemistry

Background:

• Non-electroactive polycyclic organic compounds (POCs) pose detection challenges.
• Existing methods for POCs screening often lack sensitivity or require complex procedures.
• Development of rapid, reagent-less detection methods is crucial for environmental and health monitoring.

Purpose of the Study:

• To develop a reagent-less electrochemical DNA biosensor for rapid screening and detection of non-electroactive POCs.
• To investigate the interaction mechanism between POCs and the DNA-modified electrode.
• To evaluate the sensor's sensitivity, selectivity, stability, and reproducibility.

Main Methods:

• Fabrication of a DNA/chitosan polyion complex membrane incorporating methylene blue (MB).
• Modification of a glassy carbon electrode (GCE) with the DNA-MB/chitosan complex.
• Electrochemical analysis using cyclic voltammetry to detect tetracycline hydrochloride (TC) as a model POC.
• UV-Vis absorption spectroscopy to elucidate the interaction mechanism.

Main Results:

• The modified DNA-MB/chitosan/GCE exhibited high electrochemical activity and stability.
• Tetracycline hydrochloride (TC) addition caused a significant decrease in peak current, indicating successful detection.
• A competitive interaction and displacement effect between TC and intercalated MB was proposed as the detection mechanism.
• The biosensor demonstrated high sensitivity to POCs with minimal response to common interferences.
• The electrode showed good stability and reproducibility, suitable for practical applications.

Conclusions:

• The developed reagent-less electrochemical DNA biosensor offers a sensitive and selective method for POC detection.
• The proposed mechanism involving competitive interaction provides insight into the biosensor's functionality.
• The sensor's stability and reproducibility highlight its potential for practical screening and monitoring applications.