Single-base mismatch detection based on charge transduction through DNA
High-throughput DNA sensors capable of detecting single-base mismatches are required for the routine screening of genetic mutations and disease. A new strategy for the electrochemical detection of single-base mismatches in DNA has been developed based upon charge transport through DNA films. Double-helical DNA films on gold surfaces have been prepared and used to detect DNA mismatches electrochemically. The signals obtained from redox-active intercalators bound to DNA-modified gold surfaces display a marked sensitivity to the presence of base mismatches within the immobilized duplexes. Differential mismatch detection was accomplished irrespective of DNA sequence composition and mismatch identity. Single-base changes in sequences hybridized at the electrode surface are also detected accurately. Coupling the redox reactions of intercalated species to electrocatalytic processes in solution considerably increases the sensitivity of this assay. Reporting on the electronic structure of DNA, as opposed to the hybridization energetics of single-stranded oligonucleotides, electrochemical sensors based on charge transport may offer fundamental advantages in both scope and sensitivity.
© Oxford University Press, 1999. Received April 7, 1999; Revised September 15, 1999; Accepted October 1, 1999. We wish to thank Professor F. A. Anson for several helpful discussions. This work was supported by the Camile and Henry Dreyfus Foundation (Faculty Start-up Grant to M.G.H.), the Research Corporation (M.G.H.), and the National Institutes of Health (GM49216 to J.K.B.).
Published - KELnar99.pdf