Advanced Micro and Nano-Instruments Center, School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China.
Shandong Institute of Mechanical Design and Research, Jinan, 250353, China.
Small. 2022 Jun;18(25):e2201791. doi: 10.1002/smll.202201791. Epub 2022 May 22.
Abnormal expression of microRNA-21 (miR-21) is considered to be closely associated with the pathogenesis of colorectal cancer. However, great challenges do exist for the development of ultra-sensitive biosensors to detect the abnormal expression of miR-21 due to the low concentration in serum (fm level) at the early stage of colorectal cancer. Therefore, electric field force is used to rotate and rearrange random multi-walled carbon nanotubes (MWCNTs) at the microscale to improve the active sites of the electrode in this study. The free-standing MWCNTs are densely and high-orderly embedded into the bare electrode along the direction of the electric field. Compared to the bare electrode, the peak-current response of the free-standing MWCNT electrode improves by 150 times in cyclic voltammetric measurement. A nano-genosensor based on the free-standing MWCNT electrode is developed for measuring miR-21. The nano-genosensor for miR-21 shows an ultra-high sensitivity of 48.24 µA µm , a wide linear range from 0.01 × 10 to 100 × 10 m, and a low detection limit of 1.2 × 10 m. The present nano-genosensor shows superior performance for miR-21 in human serum samples and demonstrates a potential application for the diagnosis of early stage colorectal cancer.
miR-21 的异常表达被认为与结直肠癌的发病机制密切相关。然而，由于结直肠癌早期血清中浓度较低（fm 级），开发超灵敏生物传感器来检测 miR-21 的异常表达存在巨大挑战。因此，本研究利用电场力在微尺度上旋转和重新排列随机多壁碳纳米管（MWCNTs），以提高电极的活性位点。自由站立的 MWCNTs 沿着电场的方向密集地和高序地嵌入裸电极中。与裸电极相比，自由站立 MWCNT 电极在循环伏安测量中的峰电流响应提高了 150 倍。基于自由站立 MWCNT 电极开发了用于测量 miR-21 的纳米基因传感器。miR-21 的纳米基因传感器具有超高的灵敏度为 48.24 µA µm ，从 0.01 × 10 到 100 × 10 m 的宽线性范围，以及低至 1.2 × 10 m 的检测限。该纳米基因传感器在人血清样本中对 miR-21 表现出优异的性能，并展示了用于早期结直肠癌诊断的潜在应用。
