The effect of interfacial design on the electrochemical detection of DNA and microRNA using methylene blue at low-density DNA films
Herein, we study the effect of interfacial design, specifically the orientation of a DNA probe strand, the length of the diluent and the type of target (DNA vs. microRNA), on the electrochemical response from methylene blue (MB) at low-density DNA films. The probe DNA interfaces are formed from mixe...
| Main Authors: | , , , , |
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| Format: | Journal Article |
| Published: |
Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/22721 |
| Summary: | Herein, we study the effect of interfacial design, specifically the orientation of a DNA probe strand, the length of the diluent and the type of target (DNA vs. microRNA), on the electrochemical response from methylene blue (MB) at low-density DNA films. The probe DNA interfaces are formed from mixed self-assembled monolayers of single-stranded DNA (ss-DNA) and a hydroxyl terminated alkanethiol diluents on gold surfaces. Variation in the current from the DNA-MB complex after hybridization with complementary and single adenine-cytosine mismatch DNA target is shown to depend on whether the 3' or 5' end is tethered to the electrode and the length of the diluent (6-mercapto-1-hexanol vs. 9-mercapto-1-nonanol). The sensors show better mismatch discrimination of single base pairs when both the duplexes are tethered from the 5' end to the electrode and with a longer-chain (9-mercapto-1-nonanol) diluent. Of particular note is our demonstration that the DNA/microRNA duplex exhibits greater single adenine-cytosine mismatch discrimination when compared to the corresponding DNA/DNA duplex. This study contributes to the development of selective DNA and microRNA biosensors. |
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