用亚甲基兰作为电化学活性物质进行DNA杂交的电化学检测

Electrochemical detection of DNA hybridization using methylene blue as an electrochemical hybridization indicator

【目的】研制1个以亚甲基兰(MB)为电化学活性物质的电化学DNA生物传感器。【方法】寡聚DNA探针通过-SH与Au的反应而连到金电极表面,用线性扫描伏安法检测电极表面DNA是否组装完成;用与探针DNA完全互补的ssDNA溶液与探针进行杂交反应。【结果】与目标DNA杂交后,dsDNA电极较ssDNA探针电极的峰电流显著增加,当目标DNA的浓度在5.0×10-10到1.8×10-9mol/L时,MB的峰电流与目标DNA浓度呈线性关系,检出限是5.0×10-10mol/L。【结论】用亚甲基兰(MB)作为电化学活性指示剂,具有高度的灵敏性,可成功对特定DNA片断进行选择性的识别和测定。

[Objective] To prepare an electrochemical DNA biosensor based on methylene blue （MB） as redox indicator for DNA hybridization detection. [Methods] Oligonucleotide probes with - SH at the 5＇end were attached onto the Au surface. Hybridization was induced by exposure of Au electrode to complementary ssDNA in solution. The ssDNA was detected by linear sweep vohammetry whether it was assembled on the electrode surface completely. Then probe DNA and target DNA that complement with probe DNA were used for assemble. [Results] The increases could be observed in the peak currents of dsDNA after hybridizated with complement ssDNA. The peak current of MB after hybridization with the target DNA was linearly related to the value of the target DNA concentration ranging from 5.0 × 10^-10 to 1.8 × 10^-9 mol/L. A detection limit of 5.0 × 10-10 mol/L of oligonucleotides could be estimated. [Condusion] The result suggests that this hybridization biesensor using MB as indicator of hybridization reaction can be conveniently used to monitor DNA hybridization with a high sensitivity.