Scanning electrochemical microscopy imaging of DNA microarrays using methylene blue as a redox-active intercalator.
Scanning electrochemical microscopy (SECM) has been employed in the imaging of DNA microarrays fabricated on gold substrates using methylene blue (MB) as a redox-active intercalator and ferrocyanide as the SECM mediator in solution. MB intercalated between base pairs of immobilized ds-DNA is electrochemically reduced via electron transfer from the underlying gold substrate, and the product is reoxidized in solution by SECM tip-generated ferricyanide. The resulting feedback current allows a heterogeneous electron-transfer rate constant for the MB-intercalated DNA to be deduced. Moreover, DNA microarray spots can be imaged at a detection level of 14 fmol/spot for ds-DNA consisting of 15 base pairs. Microarrays prepared using 20 microM DNA solutions are easily visualized, and the feasibility of detecting base pair mismatches is also demonstrated.
Wain
Andrew J
AJ
Department of Chemistry and Biochemistry, California State University-Los Angeles, Los Angeles, California 90032, USA.
Zhou
Feimeng
F
D020137:Base Pair Mismatch / Q000235:genetics; D004247:DNA / Q000032:analysis* / Q000737:chemistry* / Q000648:ultrastructure; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D007364:Intercalating Agents; D008751:Methylene Blue; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010084:Oxidation-Reduction; D013499:Surface Properties
D007364:Intercalating Agents; D006046:Gold; D004247:DNA; D008751:Methylene Blue