A "signal on" photoelectrochemical biosensor for miRNA-21 detection based on layer-by-layer assembled n-n type Bi2S3@CdIn2S4 heterojunction
作者全名："Cui, Ya Bin; Sun, Zhe; Qing, Min; Yu, Ling Dan; Yan, Hang; Luo, Hong Qun; Li, Nian Bing"
作者地址："[Cui, Ya Bin; Sun, Zhe; Yu, Ling Dan; Yan, Hang; Luo, Hong Qun; Li, Nian Bing] Southwest Univ, Sch Chem & Chem Engn, Key Lab Luminescence Anal & Mol Sensing, Minist Educ, Chongqing, Peoples R China; [Qing, Min] Chongqing Med Univ, Coll Pharm, Chongqing 400016, Peoples R China"
通信作者："Luo, HQ; Li, NB (通讯作者)，Southwest Univ, Sch Chem & Chem Engn, Key Lab Luminescence Anal & Mol Sensing, Minist Educ, Chongqing, Peoples R China."
来源：SENSORS AND ACTUATORS B-CHEMICAL
关键词：Photoelectrochemical biosensor; CdS quantum dots; Catalytic hairpin assembly; miRNA-21
摘要："MicroRNA (miRNA) is an ideal biomarker, and the sensitive monitoring of low-abundance miRNA is of great significance for the treatment of cancer at the onset stage. Herein, a novel Y-shaped DNA-mediated photo -electrochemical (PEC) sensing platform based on the Bi2S3@CdIn2S4 photoanode is proposed for the detection of miRNA-21. First, an n-n type Bi2S3@CdIn2S4 heterojunction with tight interface is formed for the first time through a layer-by-layer assembly strategy due to the matched band structures of Bi2S3 and CdIn2S4. The photocurrent intensity of Bi2S3@CdIn2S4/GCE electrode is 1.7-fold higher than that of Bi2S3/GCE electrode and 2.5-fold higher than that of CdIn2S4/GCE electrode under visible light irradiation. Additionally, miRNA-21-triggered catalytic hairpin assembly facilitates the formation of Y-shaped DNA structure with CdS quantum dots (CdS QDs). As the photosensitizer of Bi2S3@CdIn2S4 heterojunction, CdS QDs accelerate the separation of electron-hole pairs in the sensing system and realizes photocurrent signal enhancement, thus realizing the ""signal on"" detection of the miRNA-21. The proposed PEC biosensor exhibits a superior sensitivity of 0.18 fM and the recoveries of human serum range from 98.0% to 104% with a relative standard deviation of 5.8-8.9%. Therefore, the constructed PEC biosensor has potential application value in the early diagnosis and treatment of miRNA-related diseases."
基金机构：National Natural Science Foundation of China; Natural Science Foundation of Chongqing; ; [cstc 2020jcyj-zdxmX0003]
基金资助正文：Acknowledgments This work was supported by the National Natural Science Foundation of China (No. 21675131) and the Natural Science Foundation of Chongqing (No. cstc 2020jcyj-zdxmX0003) .