Influence of Surface Passivation on Campylobacter jejuni Specificity of an Impedimetric Genosensor for Poultry Infection Monitoring in Agri-food Industry

In our work, we propose an impedimetric genosensor for the rapid and cost-effective detection of C. jejuni for poultry infection monitoring for agri-food applications focusing on optimizing its specificity. The genosensor is based on gold electrodes functionalized with thiolated single-stranded DNA. The devices are characterized through EIS measurements, as well as with differential pulse voltammetry. The DNA presence on the electrodes’ surface is further evaluated through fluorescence spectroscopy. The electrical parameters of interest are extrapolated from EIS curves through fitting with Randles’ equivalent circuit. We test two different surface passivation with self-assembled monolayers to avoid non-specific binding. The hybridization between the probe and the complementary target DNA sequence of C. jejuni causes evident variations in the charge transfer resistance after surface passivation, about −70%. The genosensor is also tested with control solutions with non-complementary DNA and without any DNA to assess the detection specificity and the effectiveness of SAM passivation.