Gold nano-particle based Al interdigitated electrode electrical biosensor for specific ssDNA target detection

Interdigitated electrode based electrical biosensors are prominent in biosensor field. The large number of finger electrodes as comb structure gain high sensitivity through electrical measurements. Listeria monocytogenes is a serious food borne pathogen based bacterium that can cause dangerous disease to human, some infection may result in death. In here, biosensor was prepared from 1μm gap Aluminum Interdigitated Electrode (Al IDE). Functionalization steps of the Al IDE to create biosensor was based on silanization by APTES, immobilization with Gold Nano particles (GNPs) mixed single stranded Listeria synthetic probe ssDNA with Au nano-particles and blocking with tween-20. Before and after functionalization the sensor was characterized morphologically using SEM images and structurally using EDX spectra. The functionalization steps were electrically characterized using current-voltage measurements. The selectivity of the biosensor with specific target was identified electrically using complementary, non-complementary and single base mismatch ssDNA targets. Blocking step with tween-20 was important to detect target specifically. The obtained variations in current indicate the varied concentrations of Listeria targets and it is confirmed that biosensor is suitable to detect different concentrations in the range from 10 fM to 10 μM.