Highly sensitive electrochemical sensor for the detection of Shiga toxin-producing E. coli (STEC) using interdigitated micro-electrodes selectively modified with a chitosan-gold nanocomposite

•A highly sensitive, label-free electrochemical sensor was developed for the detection of the stx1 gene from STEC using silicon chips comprising interdigitated microelectrodes (IDEs).•A selective modification of sensor IDE with chitosan and probe DNA was confirmed using fluorescence.•Applying an open circuit potential to the accumulator IDE allowed a more efficient accumulation of methylene blue between double-strand DNA.•The specificity of the developed sensor was confirmed using DNA extracted from wild-type strains.