Voltammetric detection of single base-pair mismatches and quantification of label-free target ssDNA using a competitive binding assay.
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).
Pänke
Oliver
O
University of Applied Sciences Wildau, Biosystems Technology, Bahnhofstr. 1, D-15747 Wildau, Germany.
Kirbs
Andreas
A
Lisdat
Fred
F
D020137:Base Pair Mismatch / Q000235:genetics*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D017403:In Situ Hybridization / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation / Q000379:methods*; D013194:Staining and Labeling
D004277:DNA, Single-Stranded