Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
Anal Chem. 2013 Sep 3;85(17):8469-74. doi: 10.1021/ac402154z. Epub 2013 Aug 20.
We report a simple and sensitive label-free immunosensor for detection of microRNAs (miRNA) based on a conducting polymer/reduced graphene oxide-modified electrode to detect miR-29b-1 and miR-141. Square wave voltammetry is used to record the redox signal. Current increases upon hybridization (signal on) from 1 fM to 1 nM of target miRNA. The limit of quantification is ca. 5 fM. The sensor exhibits high selectivity as it distinguishes mismatch. To double-check its selectivity, two specific RNA-DNA antibodies recognizing miRNA-DNA heteroduplexes, antipoly(A)-poly(dT) and anti-S9.6, were used. The antibody complexation with the hybrid leads to a current decrease that confirms the presence of miRNA, down to a concentration of 8 fM. The antibody-hybrid complex can be then dissociated by adding miRNA-DNA hybrids in solution, causing a shift-back on the signal, i.e., an increase in the current density (signal-on). This On-Off-On detection sequence was used as a triple verification to increase the reliability of the results.
我们报道了一种基于导电聚合物/还原氧化石墨烯修饰电极的简单灵敏的无标记免疫传感器，用于检测 microRNA (miRNA)。方波伏安法用于记录氧化还原信号。杂交后电流增加（信号开启），目标 miRNA 的浓度从 1 fM 到 1 nM。定量限约为 5 fM。传感器表现出高选择性，因为它可以区分错配。为了双重检查其选择性，使用了两种特异性 RNA-DNA 抗体来识别 miRNA-DNA 异源双链体，抗多聚(A)-多聚(dT)和抗 S9.6。抗体与杂交体的复合导致电流下降，从而证实存在 miRNA，浓度低至 8 fM。然后可以通过在溶液中添加 miRNA-DNA 杂交体来解离抗体-杂交体复合物，导致信号回移，即电流密度增加（信号开启）。这种开-关-开检测序列被用作三重验证，以提高结果的可靠性。
