microRNA（miRNA）的异常表达影响RNA转录和蛋白质翻译，导致肿瘤进展和转移。如今，可靠地识别异常 miRNA 表达仍然具有挑战性，特别是在采用快速、简单和便携式检测方法时。本研究旨在以高灵敏度和特异性诊断和检测 miR-21 生物标志物。我们的检测方法包括固定 ROX 染料标记的单- 将 DNA 探针（ROX 标记的 ssDNA）连接到 MWCNT 上以检测目标 miRNA-21。最初，将 ROX 标记的 ssDNA 吸附到 MWCNT 上会导致 ROX 的荧光猝灭。随后，引入其互补DNA（cDNA）形成双链DNA（dsDNA），导致MWCNT解吸和释放，从而恢复ROX荧光。该研究检测了与miRNA-21杂交前后荧光强度的变化。荧光发射强度对 miR-21 浓度从 10-9 增加到 3.2 × 10-6 M 呈线性响应。开发的荧光传感器的检测限为 1.12 × 10-9 M。这项工作表明，使用纳米生物传感器基于碳纳米管的方法为结直肠癌 (CRC) 的早期检测提供了一种高度灵敏的方法，补充了现有技术。版权所有 © 2024，Heidarian 等人。

The abnormal expression of microRNA (miRNA) influences RNA transcription and protein translation, leading to tumor progression and metastasis. Today, reliably identifying aberrant miRNA expression remains challenging, especially when employing quick, simple, and portable detection methods.This study aimed to diagnose and detect the miR-21 biomarker with high sensitivity and specificity.Our detection approach involves immobilizing ROX dye-labeled single-stranded DNA probes (ROX-labeled ssDNA) onto MWCNTs to detect target miRNA-21. Initially, adsorbing ROX-labeled ssDNA onto MWCNTs causes fluorescence quenching of ROX. Subsequently, introducing its complementary DNA (cDNA) forms double-stranded DNA (dsDNA), which results in the desorption and release from MWCNTs, thus restoring ROX fluorescence.The study examined changes in fluorescence intensities before and after hybridization with miRNA-21. The fluorescence emission intensities responded linearly to increases in miR-21 concentration from 10-9 to 3.2 × 10-6 M. The developed fluorescence sensor exhibited a detection limit of 1.12 × 10-9 M.This work demonstrates that using a nano-biosensor based on carbon nanotubes offers a highly sensitive method for the early detection of colorectal cancer (CRC), supplementing existing techniques.Copyright © 2024, Heidarian et al.