Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
869639 | Biosensors and Bioelectronics | 2007 | 7 Pages |
The application of electrochemical techniques for DNA detection is motivated by their potential to detect hybridisation events in a more rapid, simplistic and cost-effective manner compared to conventional optical assays. Here, we present an electrochemical DNA sensor for the specific and quantitative detection of single-stranded DNA (ssDNA). Probe oligonucleotides were immobilised onto thin gold film electrodes by a 5′-thiol-linker. Hybridisation was detected by means of the electroactive redox-marker methylene blue (MB) covalently attached to the 5′-end of the target ssDNA and voltammetric techniques. MB-labeled target ssDNA was recognised down to 30 pmol. By application of a competitive binding assay, non-labeled ssDNA was detected down to 3 pmol. In addition, the DNA-modified electrodes were capable of sensing single base-pair mismatches at different positions within the sequence of the hybridised double-stranded DNA (dsDNA).