Yang Jimin, Gao Lei, Peng Cheng, Zhang Wei
School of Chemistry and Chemical Engineering, Linyi University Linyi 276005 China
RSC Adv. 2019 Mar 26;9(17):9613-9619. doi: 10.1039/c8ra10266j. eCollection 2019 Mar 22.
In this work, a novel self-signal DNA electrochemical biosensor was constructed based on tungsten disulfide (WS) nanosheets combined with poly(indole-6-carboxylic acid) (PIn6COOH) as the sensing interface. The WS nanosheets were synthesized a simple solvent exfoliation method from bulk WS, and then PIn6COOH was electropolymerized on the WS nanosheet-modified carbon paste electrode to obtain a unique nanocomposite. The electropolymerization efficiency was remarkably improved, ascribed to the physical adsorption between WS nanosheets and aromatic In6COOH monomers, resulting in an increase of the electrochemical response of PIn6COOH. Owing to the presence of π-π interactions between the conjugated PIn6COOH/WS nanocomposite and DNA bases, the probe ssDNA was noncovalently assembled on the nanocomposite substrate. After the hybridization of the probe ssDNA with the target DNA, the formation of the double-helix structure induced the resulting dsDNA to be released from the surface of the conjugated nanocomposite, accompanied with the self-signal regeneration of the nanocomposite ("signal-on"). The constructed PIn6COOH/WS nanocomposite was not only employed as an interface for DNA immobilization but also reflected the signal transduction stemming from DNA immobilization and hybridization without any external indicators or complex labeling processes. A detection limit of 2.3 × 10 mol L has been estimated and a dynamic range of 1.0 × 10 mol L to 1.0 × 10 mol L has been shown for the detection of a PIK3CA gene related to lung cancer. Selectivity of the biosensor has been researched in the presence of noncomplementary and base mismatched DNA sequences.
在本工作中，基于二硫化钨（WS）纳米片与聚（吲哚 - 6 - 羧酸）（PIn6COOH）结合作为传感界面构建了一种新型自信号DNA电化学生物传感器。WS纳米片通过简单的溶剂剥离法由块状WS合成，然后将PIn6COOH电聚合在WS纳米片修饰的碳糊电极上以获得独特的纳米复合材料。电聚合效率显著提高，这归因于WS纳米片与芳香族In6COOH单体之间的物理吸附，导致PIn6COOH的电化学响应增加。由于共轭的PIn6COOH/WS纳米复合材料与DNA碱基之间存在π - π相互作用，探针单链DNA非共价组装在纳米复合材料基底上。探针单链DNA与靶DNA杂交后，双螺旋结构的形成促使所得双链DNA从共轭纳米复合材料表面释放，同时伴随着纳米复合材料的自信号再生（“信号开启”）。构建的PIn6COOH/WS纳米复合材料不仅用作DNA固定的界面，还能反映DNA固定和杂交产生的信号转导，无需任何外部指示剂或复杂的标记过程。对于与肺癌相关的PIK3CA基因检测，估计检测限为2.3×10⁻¹² mol/L，动态范围为1.0×10⁻¹¹ mol/L至1.0×10⁻⁷ mol/L。在存在非互补和碱基错配DNA序列的情况下研究了生物传感器的选择性。
