miRNA-21作为肺癌标志物的方便高效的测定方法的开发对癌症早期预防具有重要意义。本研究利用点击反应和光催化原子转移自由基聚合(光-ATRP)技术成功制备了一种电化学生物传感器，通过蓝光激发下的反应，可检测miRNA-21。通过使用发夹结构的DNA作为识别探针，该电化学传感器可在光催化剂(荧光素)和五甲基二乙基三胺的反应下，在电极表面沉积大量具有电活性的单体(铁爪基甲基丙烯酸甲酯)，从而实现信号放大。该生物传感器对miRNA-21具有高灵敏、高精准、高选择性的特点，并且对具有不同碱基错配的RNA具有很高的特异性。在最佳条件下，该生物传感器在10 fM至1 nM的范围内显示出线性关系(R2=0.995)，检测限为1.35 fM。此外，该生物传感器在血清样本中对RNA的分析表现出良好的抗干扰性能。该传感器基于绿色化学原理，具有成本低、特异性强、抗干扰能力强等优点，在实现检测目标的同时提供经济效益，对复杂样本的分析具有极大的前景。版权所有©2023 Elsevier B.V. All rights reserved.

The development of a convenient and efficient assay using miRNA-21 as a lung cancer marker is of great importance for the early prevention of cancer. Herein, an electrochemical biosensor for the detection of miRNA-21 was successfully fabricated under blue light excitation using click chemistry and photocatalytic atom transfer radical polymerization (photo-ATRP). By using hairpin DNA as a recognition probe, the electrochemical sensor deposits numerous electroactive monomers (ferrocenylmethyl methacrylate) on the electrode surface under the reaction of photocatalyst (fluorescein) and pentamethyldiethylenetriamine, thereby achieving signal amplification. This biosensor is sensitive, precise and selective for miRNA-21, and is highly specific for RNAs with different base mismatches. Under optimal conditions, the biosensor showed a linear relationship in the range of 10 fM ∼1 nM (R2 = 0.995), with a detection limit of 1.35 fM. Furthermore, the biosensor exhibits anti-interference performance when analyzing RNAs in serum samples. The biosensor is based on green chemistry and has the advantages of low cost, specificity and anti-interference ability, providing economic benefits while achieving detection objectives, which makes it highly promising for the analysis of complex samples.Copyright © 2023 Elsevier B.V. All rights reserved.