A label-free DNA sensor based on impedance spectroscopy

摘要: Abstract This paper describes a label-free detection system for DNA strands based on gold electrodes and impedance measurements. A single-stranded 18 mer oligonucleotide (ssDNA) was immobilised via thiol linker film served as probe DNA. Residual binding places were filled with mercaptobutanol. The sensor surface clearly distinguished between complementary non-complementary target ssDNA. Additionally, of single base pair mismatches possible. electrode impedimetrically characterised in the presence redox ferri/ferrocyanide before after hybridisation. Impedance analysis showed that charge transfer resistance, R ct , increasing duplex formation, whereas capacitive properties remain rather unaltered. relative change used parameter. Concentrations nanomolar range have been detected by system. reusable because denaturation protocol allowed effective double strand dissociation without changing substantially. time reduced to about 15 min including regeneration. signal amplified 20% negatively charged molecule formed duplex. also capable sensing longer ssDNA shown 25 mer 37 mer oligonucleotides.