DNA
吸附
检出限
化学
牛血清白蛋白
电极
生物传感器
分析物
杂交探针
组合化学
色谱法
生物物理学
纳米技术
材料科学
生物化学
生物
有机化学
物理化学
作者
Haiyan Dong,Zheng Ming,Mingduan Chen,Danting Song,R. Stephanie Huang,Aiwen Zhang,Haiying Wen,Jia Lee,Junyang Zhuang
标识
DOI:10.1016/j.bios.2022.114911
摘要
The assay performance of electrochemical DNA (E-DNA) sensors is deeply influenced by the state of DNA probes immobilized on electrode. Moreover, the immobilization procedures for DNA probes are tedious and vary according to the probes and analytes. In this work, we find that the adsorption layers of bovine serum albumin (BSA) on gold electrode (AuE) possess a size exclusion effect to distinguish between single-stranded (-ss) DNA probes and the DNA fragments generated from enzymatic digestion of ssDNA probes. In detail, the BSA layers act as a gatekeeper that hinders the adsorption of a ssDNA probe on AuE but permits the DNA fragments with much smaller sizes to pass through the adsorption layers and adsorb on AuE. This finding is developed into a novel E-DNA sensor for microRNA (miRNA) detection by coupling with duplex-specific nuclease (DSN)-assisted target recycling strategy. The ssDNA probe in solution phase is enzymatically digested during the DSN-assisted target recycling process initiated by target miRNA-21, generating plenty of DNA fragments. The adsorption of these DNA fragment on BSA/AuE is permitted, which arouses electrochemical signals after binding with [Ru(NH3)6]3+ to indicate the recognition of miRNA-21. The developed E-DNA sensor possesses a wide calibration range from 0.001 to 100 pM and a low detection limit of 0.48 fM. Significantly, accurate evaluation of miRNA-21 expression levels in cancer cell lines and non-small-cell lung carcinomas (NSCLC) serum samples are successfully achieved using the developed method. This work provides a new mechanism for constructing sensitive E-DNA sensor without tedious probe immobilization procedures.
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