title: Detection of single-base mismatch at distal end of DNA duplex by electrochemical impedance spectroscopy.
abstract: Herein, we report an anomalous electrochemical behavior of surface-bound DNA duplex that has single-base mismatches at its distal end. Single-stranded 15-base DNA was immobilized at its 5'end onto gold electrode surfaces. After hybridization with complementary or mismatched DNA, electrochemical impedance spectra were obtained using [Fe(CN)(6)]3-/4- as redox marker ions. Hybridization with the complementary DNA reduced the charge-transfer resistance (R(CT)), whereas single-base mismatches at the distal end of the duplex largely increased the R(CT). This anomaly was found only with the distal end: the increase in R(CT) was not observed for mismatches at either the middle or the proximal end. These results indicate that electrochemical detection of single-base alterations at an end of sample DNA is exceptionally easy because of the diametrically opposite responses. This detection principle is promising for the typing of single-nucleotide polymorphisms in combination with the single-base primer extension protocol.
authors.affiliation: Bioengineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ito
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hosokawa
authors.forename: Mizuo
authors.initials: M
authors.lastname: Maeda
mesh_terms: D020137:Base Pair Mismatch; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis*; D017097:Electric Impedance; D004563:Electrochemistry / Q000379:methods*; D020641:Polymorphism, Single Nucleotide; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D004247:DNA