PlcA-based nanofabricated electrochemical DNA biosensor for the detection of Listeria monocytogenes in raw milk samples

The electrochemical DNA biosensor has been developed for the detection of Listeria monocytogenes in raw milk samples. The electrochemical studies of the developed biosensor was recorded by cyclic voltammetry (CV) and electrochemical impedance (EI) using methylene blue (MB) and potassium ferricyanide K₃Fe(CN)⁻₆ as redox indicators. The selectivity of the developed biosensor was demonstrated using complementary and mismatch oligonucleotide sequences. The sensitivity (S) of the developed sensor was recorded as 3461 (μA/cm²)/ng and limit of detection (LOD) was found to be 82 fg/6 µl with the regression coefficient (R²) 0.941 using CV. The sensor was characterized by field emission scanning electron microscopy (FE-SEM). The electrode was found to be stable for six months, with only 10% loss in the initial CV current.