Department of Pediatric Neurosurgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.
Shanghai Institute of Pediatric Research, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.
Mikrochim Acta. 2022 Feb 14;189(3):105. doi: 10.1007/s00604-022-05210-y.
Monitoring of cerebrospinal fluid (CSF) microRNAs (miRs) offers a promising option for the diagnosis and management of patients with central nervous system tumors. However, the sensitive detection of miRs in clinical CSF samples has been hindered by the ultra-low abundance of target miRs. Here, we report an electrochemical biosensor for the highly sensitive label-free detection of CSF miR-21 relying on target-induced redox signal amplification (eTIRSA). The biosensor was developed by covalently assembling the capture stands partially complementary to miR-21 on the gold nanoparticle-coated glassy carbon electrode. In the presence of miR-21, the short capture stand hybridized with the partial bases of miR-21, allowing the rest sequence of the target molecule to further bind with a long guanine-rich sequence which could specifically adsorb a number of methylene blue indicators, thus generating an amplified electrochemical redox signal, typically at a working potential of - 0.19 V (vs. SCE). The response of the surface-bound methylene blue indicators was positively correlated to the concentration of miR-21, providing a dynamic range of 0.5-80 pM and a limit of detection down to 56 fM. Moreover, the eTIRSA biosensor had high specificity with single-base resolution and exhibited good performance for label-free quantification of miR-21 in medulloblastoma cell extracts and clinical CSF samples and for accurate discrimination of medulloblastoma against non-cancer controls, indicating its potential application in CSF miR-based liquid biopsy of brain cancers.
监测脑脊液（CSF）microRNAs（miRs）为中枢神经系统肿瘤患者的诊断和治疗提供了一种很有前途的选择。然而，由于目标 miR 含量极低，临床 CSF 样本中 miR 的敏感检测受到了阻碍。在这里，我们报道了一种基于目标诱导的氧化还原信号放大（eTIRSA）的电化学生物传感器，用于高度敏感的无标记 CSF miR-21 检测。该生物传感器通过将与 miR-21 部分互补的捕获支架共价组装在金纳米粒子涂覆的玻碳电极上而开发。在存在 miR-21 的情况下，短的捕获支架与 miR-21 的部分碱基杂交，允许目标分子的其余序列与富含鸟嘌呤的长序列进一步结合，该序列可以特异性地吸附大量亚甲基蓝指示剂，从而产生放大的电化学氧化还原信号，通常工作电位为-0.19 V（相对于 SCE）。表面结合的亚甲基蓝指示剂的响应与 miR-21 的浓度呈正相关，提供了 0.5-80 pM 的动态范围和低至 56 fM 的检测限。此外，eTIRSA 生物传感器具有高特异性和单碱基分辨率，可用于无标记定量检测髓母细胞瘤细胞提取物和临床 CSF 样本中的 miR-21，并可准确区分髓母细胞瘤与非癌症对照，表明其在基于 CSF miR 的脑癌液体活检中的潜在应用。
