School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China; Department of Cardiac Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 610072, China.
Department of Oncology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
Int J Biol Macromol. 2024 Nov;279(Pt 4):135370. doi: 10.1016/j.ijbiomac.2024.135370. Epub 2024 Sep 13.
MicroRNAs (miRNAs) play an important role in the process of heart failure (HF) and are emerging biomarkers that can be used for the auxiliary diagnosis of HF. However, it is very challenging to accurately analyze the expression levels of trace miRNAs in complex clinical samples. Here, we developed an enzyme-free colorimetric sensor for the ultrasensitive detection of miRNA-423-5p (HF-associated miRNA) based on three-dimensional DNA walkers constructed from functional nucleic acids and gold nanoparticles (AuNPs). DNAzyme with cleavage activity was specifically activated by miRNA-423-5p to sustainably cleave the substrate, thereby releasing the trigger sequence to initiate the subsequent mismatched catalytic hairpin assembly (MCHA) cycle. Then, as the MCHA cycle proceeded to continuously expose the G-quadruplex (GQ) sequence, the sequence bound with hemin to form a large amount of GQ/hemin DNAzyme on the surface of the AuNPs, which rapidly catalyzed the chromogenic oxidation of 3,3',5,5'-tetramethylbenzidine to yield an amplified colorimetric signal readout. The colorimetric sensor exhibited an ultralow detection limit (32 fM), showed excellent specificity and performed well in serum samples. The sensor was applied to detect miRNA-423-5p in clinical plasma samples from healthy individuals and HF patients, and the results revealed its good clinical application in HF diagnosis. Thus, the developed colorimetric sensor provides a convenient detection tool for early screening and diagnosis of HF, as well as for pathophysiological studies.
微小 RNA（miRNAs）在心力衰竭（HF）过程中发挥着重要作用，并且是新兴的生物标志物，可用于 HF 的辅助诊断。然而，在复杂的临床样本中准确分析痕量 miRNA 的表达水平极具挑战性。在这里，我们基于功能核酸和金纳米粒子（AuNPs）构建的三维 DNA 行走者，开发了一种用于超灵敏检测 miRNA-423-5p（与 HF 相关的 miRNA）的无酶比色传感器。具有切割活性的 DNAzyme 被 miRNA-423-5p 特异性激活，以持续切割底物，从而释放触发序列以启动随后的错配催化发夹组装（MCHA）循环。然后，随着 MCHA 循环继续不断暴露 G-四链体（GQ）序列，与血红素结合的序列在 AuNPs 表面形成大量 GQ/血红素 DNAzyme，其迅速催化 3,3',5,5'-四甲基联苯胺的显色氧化，产生放大的比色信号读数。比色传感器表现出超低的检测限（32 fM），表现出优异的特异性，并在血清样本中表现出色。该传感器用于检测来自健康个体和 HF 患者的临床血浆样本中的 miRNA-423-5p，结果表明其在 HF 诊断中具有良好的临床应用。因此，开发的比色传感器为 HF 的早期筛查和诊断以及病理生理学研究提供了一种便捷的检测工具。
