一次性信号放大电化学阻抗RNA传感器研究

Study on a disposable signal amplification electrochemical impedance RNA sensor

以自制的丝网印刷碳电极(SPCE)为基体电极,利用DNA四面体纳米探针和酶催化信号放大构建了一个一次性电化学阻抗型RNA传感器.固定在AuNPs修饰的SPCE表面的DNA四面体结构能确保DNA探针具有可控的密度和方向,结合辣根过氧化物酶(HRP)催化H2O2氧化4-氯-1-萘酚(CN)的反应,生成不溶物沉积在电极表面,有效地放大电化学阻抗信号,实现了miRNA的高灵敏阻抗测定.检测限可以低至1.0pmol/L,阻抗值和miRNA-141浓度的对数在3.0~1000pmol/L之间具有良好的定量关系.

A disposable electrochemical impedance RNA sensor was fabricated based on homemade screen printed carbon electrode (SPCE) and enzyme-catalyzed signal amplification reaction.The SPCE was modified with AuNPs through electrodeposition and subsequently functionalized with-SH of the DNA nanostructure,which can ensure that the DNA probe has a controllable density and direction.Hydrogen peroxide (HRP) can catalyze oxidation reaction of H2O2 and 4-chloro-1-naphthol (CN) to produce an insoluble precipitate accumulated on the electrode surface,which caused the electron-transfer resistance of the sensor increased greatly.According to the above,signal amplification detection of the target microRNA can be carried out.The proposed method could detect target miRNA at a linear range from 3.0 pmol/L to 1 000 pmol/L,with a detection limit of 1.0 pmol/L.