Yang Jimin, Yin Xuesong, Xia Min, Zhang Wei
School of Chemistry and Chemical Engineering, Linyi University Linyi 276005 China
RSC Adv. 2018 Nov 27;8(69):39703-39709. doi: 10.1039/c8ra08669a. eCollection 2018 Nov 23.
Tungsten disulfide (WS) nanosheets supported poly(xanthurenic acid) (PXa) was used as the signal transduction interface for electrochemical genosensing. The WS nanosheets were obtained from bulk WS using a simple ultrasonic method. Due to the unique physical adsorption of Xa monomers to WS, the electropolymerization efficiency was greatly improved, accompanied with an increased electrochemical response of PXa. The obtained PXa/WS nanocomposite not only served as a substrate for DNA immobilization but also reflected the electrochemical transduction originating from DNA immobilization and hybridization without any other indicators or complicated labelling steps. Owing to the presence of abundant carboxyl groups, the probe ssDNA was covalently attached on the carboxyl-terminated PXa/WS nanocomposite through the free amines of DNA sequences based on the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and -hydrosulfosuccinimide crosslinking reaction. The covalently immobilized probe ssDNA could selectively hybridize with its target DNA to form dsDNA on the surface of the PXa/WS nanocomposite. This developed biosensor achieved a satisfactory detection limit down to 1.6 × 10 mol L and a dynamic range of 1.0 × 10 to 1.0 × 10 mol L for detection of circulating tumor DNA related to gastric carcinoma. Selectivity of the biosensor has been investigated in presence of non-complementary, one-mismatched and two-mismatched DNA sequences.
二硫化钨（WS）纳米片负载的聚（黄尿酸）（PXa）被用作电化学基因传感的信号转导界面。WS纳米片通过简单的超声方法从块状WS中获得。由于Xa单体对WS的独特物理吸附，电聚合效率大大提高，同时PXa的电化学响应增强。所获得的PXa/WS纳米复合材料不仅作为DNA固定的底物，而且在没有任何其他指示剂或复杂标记步骤的情况下反映了源自DNA固定和杂交的电化学转导。由于存在丰富的羧基，基于1-乙基-3-（3-二甲基氨基丙基）碳二亚胺和N-羟基琥珀酰亚胺交联反应，探针单链DNA通过DNA序列的游离胺共价连接到羧基封端的PXa/WS纳米复合材料上。共价固定的探针单链DNA可以与其靶DNA选择性杂交，在PXa/WS纳米复合材料表面形成双链DNA。这种开发的生物传感器对与胃癌相关的循环肿瘤DNA的检测下限达到了令人满意的1.6×10⁻¹² mol/L，动态范围为1.0×10⁻¹¹至1.0×10⁻⁷ mol/L。在存在非互补、一个错配和两个错配DNA序列的情况下研究了该生物传感器的选择性。
