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制备了一种基于氧化石墨烯作为传感平台的无标记DNA传感器。探针DNA通过π-π堆积作用固定到氧化石墨烯表面,电化学交流阻抗法作为传感表征及检测技术。当传感器识别目标DNA时,由于形成双链结构,双链DNA离开氧化石墨烯表面,进入溶液,使得电化学阻抗值减小。因此,可以利用杂化前后DNA传感器所展现出阻抗值的差异,实现对目标DNA的定量检测。结果表明:目标DNA浓度在1.0×10-8~1.0×10-12mol/L范围内,阻抗值变化与目标DNA浓度的对数呈线性关系,检出限为3.5×10-13mol/L(S/N=3)。此外,传感器能区分互补单碱基错配、完全错配的DNA序列。
A label-free DNA sensor based on graphene oxide as sensing platform was prepared. The probe DNA is fixed to the surface of graphene oxide by π-π stacking, and the electrochemical AC impedance method is used as the sensing and detection technology. When the sensor recognizes the target DNA, the double-stranded DNA leaves the surface of the graphene oxide and enters the solution due to the formation of a double-stranded structure, so that the electrochemical impedance value is reduced. Therefore, the difference between the impedance values exhibited by the DNA sensors before and after hybridization can be utilized to achieve the quantitative detection of the target DNA. The results showed that the target DNA concentration ranged from 1.0 × 10-8 to 1.0 × 10-12 mol / L, and the change of impedance was linear with the logarithm of target DNA concentration. The detection limit was 3.5 × 10-13 mol / L (S / N = 3). In addition, the sensor can distinguish between complementary single-base mismatched, completely mismatched DNA sequences.