DNA barcode-based detection of exosomal microRNAs using nucleic acid lateral flow assays for the diagnosis of colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related deaths worldwide. The standard methods for diagnosing CRC, endoscopy and tissue biopsy, are invasive and time-consuming. Herein, we propose a novel method for the accurate and non-invasive diagnosis of CRC based on the analysis of exosomes that are circulating in biological fluids using a DNA barcode-based nucleic acid lateral flow assay (NALFA). Our technology combines reverse transcription using a stem-loop primer with DNA barcode-based NALFA. A colorimetric signal is generated only in the presence of the target exosomal miRNA, which can be determined even with the naked eye. The proposed system successfully detected miR-92a and miR-141, which are overexpressed in CRC exosomes. Moreover, when applied to plasma samples from CRC patients, our system simultaneously detected multiple markers in one strip. By combining these markers, we achieved high analytical performance with a sensitivity and a specificity of 95.24% and 100.0%, respectively, demonstrating that the proposed assay can be a simple diagnostic platform for the detection of exosomal miRNA.