Lab on a single microbead: an ultrasensitive detection strategy enabling microRNA analysis at the single-molecule levelElectronic supplementary information (ESI) available. See DOI: 10.1039/c5sc02641e

• Main Authors: Zhang, Xiaobo, Liu, Chenghui, Sun, Lingbo, Duan, Xinrui, Li, Zhengping
• Format: Journal Article
• Language: English
• Published: 13.10.2015
• DOI: 10.1039/c5sc02641e
• ISSN: 2041-6520

Detection of a single nucleic acid molecule is of great significance for both fundamental biochemistry studies and clinical diagnostics. By using microRNA (miRNA) as a model target, herein, we have developed a single-microbead-based sensing (SMBS) platform, which simply enables the detection of miRNA at the single-molecule level. In this strategy, an isothermal exponential amplification reaction (EXPAR) is rationally designed towards specific miRNAs and all products of the EXPAR are integrated onto a single microbead for signal amplification and fluorescence enrichment. This pushes the detection of miRNAs down to 1 aM in a 5 μL sample, corresponding to 3 copies of the miRNA molecule. This new strategy also affords high selectivity and it is capable of distinguishing among homologous miRNA family members even with a single-base difference. Due to its ultrahigh sensitivity and selectivity, the proposed SMBS platform has been successfully applied to the detection of miRNA extracted from a single cell. A single microbead-based sensing platform has been developed, which enables the detection of microRNA at the single-molecule level.