Chiang Mai Journal of Science

In this work, a simplified two-electrode configuration metal-free screen-printed carbon electrode (2-MFSPCE) was fabricated in-house and electrochemically evaluated. The electrode performance of the 2-MFSPCE was preliminary characterized with ferricyanide by using cyclic voltammetry (CV). The electroactivity of  TMB (3,3’,5,5’-tetramethylbenzidine) substrate on 2-MFSPCE was studied before the development of a Horseradish peroxidase (HRP) enzyme-based electrochemical genosensor detection platform for specific 40 mer-synthetic target DNA sequence from food-borne pathogen, Vibrio cholerae lolB gene. The CV results showed that the electron transfer/conductivity on 2-MFSPCE was highly consistent and stable without any significant shifting. In addition, there was good electrochemical reproducibility that all individual 2-MFSPCE (within and between batches of fabrication) showed relative low variation in electroanalysis. A detection potential (reduction potential) of ­­−0.1 V was empirically determined on 2-MFSPCE for enzymatic product from HRP/TMB catalytic reaction. By using two-step sandwich-type hybridization strategy, the chronoamperometric analysis of the enzyme-based electrochemical genosensor with 2-MFSPCE as transducer bestowed a detection limit of 5 fM of target sequence. The encouraging results obtained from the electrochemical characterization and the well response in electrochemical genosensor study indicating the feasibility of this 2-MFSPCE to use as a low-cost disposable electrode in electrochemical sensor application.