Department of Biochemistry, Panjab University, Chandigarh, 160014, India.
Mikrochim Acta. 2019 Feb 15;186(3):185. doi: 10.1007/s00604-019-3302-3.
An electrochemical hybridization assay is described for the determination of microRNA-21. Fluorine tin oxide (FTO) sheets were coated with carboxylated graphene oxide followed by deposition of gold-platinum bimetallic nanoparticles by using chronoamperometry at a potential of -0.2 V for 350 s. The capture probe was immobilized on the surface of the modified FTO sheets by biotin-avidin interaction. On exposure to microRNA-21, hybridization occurs, and that can be detected at a relatively low working potential of 0.25 V by using ferri/ferro-cyanide as an electrochemical probe. The various modifications of the FTO sheets were characterized by means of FE-SEM, FT-IR, contact angle studies and electrochemical techniques. The effects of pH value, EDC-NHS activation time, concentration of capture probe and incubation time were optimized. The sensor has a wide linear response that extends from 1 fM to 1 μM of microRNA-21, and the detection limit is 1 fM. The sensor is stable for about 15 days (by retaining 90% of its initial activity) and can be reused for about 3 times (85% of initial activity) after regeneration with 50 mM NaOH solution. The sensor was applied to the analysis of spiked human serum and gave recoveries between 90 and 111%. Graphical abstract Carboxylated graphene oxide (CGO) coated on a fluorine tin oxide (FTO) electrode was decorated with Au-Pt bimetallic nanoparticles (Au-PtBNPs). The Au-PtBNPs/CGO/FTO electrode surface was used for immobilizing streptavidin and biotinylated capture probe which can electrochemically detect microRNA-21 based on its sequence complementarity.
电化学杂交分析测定 microRNA-21。在 -0.2 V 的电位下通过计时安培法在氟掺杂氧化锡 (FTO) 片上涂覆羧基化石墨烯氧化物，然后沉积金-铂双金属纳米粒子 350 s。通过生物素-亲和素相互作用将捕获探针固定在修饰后的 FTO 片表面上。暴露于 microRNA-21 后，发生杂交，并且可以通过使用铁氰化亚铁作为电化学探针在相对较低的工作电位 0.25 V 下进行检测。通过 FE-SEM、FT-IR、接触角研究和电化学技术对 FTO 片的各种修饰进行了表征。优化了 pH 值、EDC-NHS 活化时间、捕获探针浓度和孵育时间的影响。传感器具有从 1 fM 到 1 μM 的 microRNA-21 的宽线性响应，检测限为 1 fM。传感器在大约 15 天内稳定（保留初始活性的 90%），并且可以在再生后重复使用大约 3 次（初始活性的 85%）用 50 mM NaOH 溶液。该传感器用于分析加标人血清，并给出了 90%至 111%的回收率。
