Electronic detection of target nucleic acids by a 2,6-disulfonic acid anthraquinone intercalator.
A DNA hybridization biosensor based on long-range electron transfer that is capable of detecting DNA single-base mismatch is presented. A mixed self-assembled monolayer of single-stranded DNA (ss-DNA), thiolated at the 3' end, and 6-mercapto-1-hexanol was formed on a gold surface. This probe ss-DNA-modified gold surface was incubated in 2,6-disulfonic acid anthraquinone (AQDS) intercalator solution, rinsed, and placed in an AQDS-free buffer solution, whereupon voltammetric experiments were performed. No voltammetric peaks were observed for probe ss-DNA-modified gold electrodes. Upon DNA hybridization and incubation in AQDS, clear voltammetric peaks, consistent with the oxidation and reduction of AQDS, were observed. The absence of AQDS electrochemistry for ss-DNA-modified surfaces clearly shows the electrochemistry is due to long-range electron transfer through the DNA duplex. No peak currents were observed when the probe ss-DNA-modified surface was exposed to noncomplementary target DNA, but there was a diminution in current signal upon hybridization with C-A mismatched and a G-A mismatched targets.
School of Chemical Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
Elicia L S
EL
Wong
J Justin
JJ
Gooding
D000880:Anthraquinones / Q000737:chemistry*; D020137:Base Pair Mismatch; D015374:Biosensing Techniques / Q000379:methods*; D015342:DNA Probes / Q000032:analysis / Q000235:genetics; D004563:Electrochemistry; D004566:Electrodes; D004581:Electronics; D007364:Intercalating Agents / Q000032:analysis* / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D009696:Nucleic Acids / Q000032:analysis* / Q000737:chemistry / Q000235:genetics
C487797:2,6-disulfonic acid anthraquinone; D000880:Anthraquinones; D015342:DNA Probes; D007364:Intercalating Agents; D009696:Nucleic Acids