Ultrasensitive electrochemical detection of microRNA-21 combining layered nanostructure of oxidized single-walled carbon nanotubes and nanodiamonds by hybridization chain reaction

作者：Liu Lingzhi; Song Chao; Zhang Zhang; Yang Juan; Zhou Lili; Zhang Xing; Xie Guoming^*

来源：Biosensors and Bioelectronics, 2015, 70: 351-357.

DOI：10.1016/j.bios.2015.03.051

• MicroRNA-21
• Oxidized single-walled carbon nanotubes
• Nanodiamonds
• Tetrahedron-structured probes
• Hybridization chain reaction

Measurement of microRNA (miRNA) levels in body fluids is a crucial tool for the early diagnosis and prognosis of cancers. In this study, we developed an electrochemical assay to detect miRNA-21 by fabricating the electrode with layer-by-layer assembly of oxidized single-walled carbon nanotubes and nanodiamonds. Tetrahedron-structured probes with free-standing probe on the top served as receptors to hybridize with target miRNA directly. The probes were immobilized on the deposited gold nano-particles through a well-established strong Au-S bond. The electrochemical signal was mainly derived from an ultrasensitive pattern by combining hybridization chain reaction with DNA-functionalized AuNPs, which provided DNAzyme to catalyze H2O2 reduction. Differential pulse voltammetry was applied to record the electrochemical signals, which was increased linearly with the target miRNA-21, and the linear detection range was 10 fM to 1.0 nM. The limit of detection reached 1.95 fM (S/N=3), and the proposed biosensor exhibited good reproducibility and stability, as well as high sensitivity. Hence, this biosensor has a promising potential in clinical application.

• 出版日期2015-8-15
• 单位重庆医科大学