Capacitance sensor system for oligonucleotide hybridization detection

In this paper, we describe an electronic method of oligonucleotide detection implemented in silicon chips. The detection system includes an interdigitated chip and capacitance detection circuit. Interdigitated microelectrodes were microfabricated with a width of 10 μm, a gap of 3 μm, and a total length of 3,320 μm. Oligonucleotide detection was tested on an electrode surface precoated with a functional monolayer by a self-assembly technique. In this study, oligonucleotide detection used the fundamental hybridization of the complementary strand. To enhance the capacitance change in oligonucleotide detection, we used the sandwich conjugation method with the Au nanoparticles cross-linked at the end of a single DNA strand. The detection system was designed to automatically measure the individual capacitances of oligonucleotides detected from the array chip. The capacitance of a biomolecule was measured using comb-shaped electrodes and, due to DNA hybridization, the capacitance increased by 20.31%. In this work, we successfully developed a multipoint capacitance sensor that offers the potential to detect different sequences in the future.