Electrochemical DNA Sensor Designed Using the Pencil Graphite Electrode to Detect Listeria monocytogenes

Area of Science:

• Electrochemistry
• Biosensors
• Molecular Diagnostics

Background:

• Pathogenic *Listeria monocytogenes* pose a significant public health risk.
• Accurate and rapid detection methods are crucial for food safety and clinical diagnostics.
• Existing detection methods may lack specificity or speed.

Purpose of the Study:

• To develop a novel electrochemical DNA sensor for the specific detection of *Listeria monocytogenes*.
• To optimize sensor design using modified pencil graphite electrodes and specific gene targets.
• To evaluate the sensor's performance in terms of sensitivity and analysis time.

Main Methods:

• Design of an electrochemical sensor using modified pencil graphite electrodes (activated or polypyrrole-coated).
• Selection of two target gene fragments: *hlyA* (pathogenicity-specific) and 16S RNA (genus-specific).
• Hybridization of immobilized DNA probes with target DNA, followed by differential pulse voltammetric detection of guanine oxidation.

Main Results:

• The optimal sensor configuration utilized a polypyrrole-coated pencil graphite electrode and the 702 bp *hlyA* gene fragment.
• The developed sensor achieved high sensitivity with determined DNA concentrations of 8.2 × 10^-11 M for *hlyA* and 2.7 × 10^-10 M for 16S RNA.
• The analysis time was successfully reduced to under one hour.

Conclusions:

• A novel, highly sensitive electrochemical DNA sensor for *Listeria monocytogenes* detection was successfully developed.
• The sensor's performance was optimized using a polypyrrole-modified electrode and the *hlyA* gene target.
• This sensor offers a rapid and efficient alternative for identifying pathogenic *Listeria monocytogenes* strains.