In this regard, chitosan, a natural polymer, has gained a lot of attention as it is rich in amine groups, thereby allowing subsequent covalent attachment of a range of biomolecules . It has been widely used in the development of DNA based biosensors, where typically the probe DNA modified with an amine group is attached to the polymer using glutaraldehyde as a linker . Since it is a non-conductive polymer, several researchers have combined it with other conductive 0D, 1D, and 2D materials , , , to enhance the electrical conductivity and therefore the sensitivity of detection. However, these modifications can be complex, e.g., require several steps, high temperatures, and thus increase the complexity of sensor development . In contrast, Du, Luo , developed a simple, one-step co-electrodeposition technique for chitosan with simultaneous deposition of gold nanoparticles on large 2 mm diameter electrodes. Their technique was applied for glucose detection and no biomolecule attachment was tested in their work. In this work, gold IDEs fabricated on silicon chips were used for the development of a voltammetric sensor allowing highly sensitive detection of the STEC virulence gene, stx1. The sensor IDE was specifically modified with Cht-Au nanocomposite and probe DNA leaving the other IDE (accumulator IDE) unmodified, confirmed with optical and fluorescent microscopy. This accumulator IDE was then used to pre-concentrate a redox probe, MB, around the sensor IDE by applying open circuit potential (OCP), enhancing the hybridisation signal and increasing sensitivity. To the best of our knowledge, interdigitated electrodes have never been utilised to enhance molecule accumulation for DNA detection. By this approach, we have managed to achieve highly sensitive detection of 100 aM and detection of chromosomal DNA without the amplification step. This non-complex method of electrode modification and DNA detection has the potential to be applied to multiplex detection of different DNA strands in the future.