Single polydiacetylene microtube waveguide platform for discriminating microRNA-215 expression levels in clinical gastric cancerous, paracancerous and normal tissues.

MicroRNAs (miRNAs) have emerged as novel biomarkers for human early-phase cancer diagnosis and disease prevention recently. Herein, we reported a novel miRNA-215 targeting biosensor, which was based on single polydiacetylene (PDA) microtube waveguide system integrated with sandwich-type hybridization design and condensing enrichment effect. The target miRNA could be captured by oligonucleotides conjugated on the surface of PDA microtube and Au nanorod (AuNR) respectively, resulting in the out-coupled fluorescence of PDA microtube quenching. In this strategy, the formation of a sandwich structure, as a result of co-hybridization of the target miRNA, enabled simplified preparation process, enhanced reaction efficiency, and increased recyclability and stability of the platform. Based on condensing enrichment effect, the co-hybridization reaction could be enriched on the surface of microtube and the proposed platform could easily achieve highly sensitive detection of miRNA-215 in one step. Remarkably, this platform could be directly applied to discriminate the miRNA-215 expression levels in clinical gastric cancerous, paracancerous and normal tissues samples. This assay offers a simple and convenient method for miRNA quantification in clinical samples, even with the potential for invasive, portable equipment for early clinical diagnosis of diseases.