SERS and lateral flow assay-based test strips for rapid and efficient detection of GC-associated miR-19a-3p and miR-4491

MicroRNA (miRNA) is a potential biomarker for tumor diagnosis. Therefore, it is important to investigate a method for accurate analysis of miRNA. In this study, we developed a novel and cost-effective surface-enhanced Raman scattering (SERS)-lateral flow assay(LFA) dual detection line test strip for quantitatively detecting miR-19a-3p and miR-4491, respectively. These two miRNAs are closely associated with the development of gastric cancer (GC) and their significant overexpression in patients gives them great potential as innovative tumor markers for GC detection. During the detection process, miR-19a-3p and miR-4491 would compete for binding to the corresponding SERS tags. The presence of concentrations of miR-19a-3p and miR-4491 in the sample solution reduces the binding of the SERS tags to the ssDNAs, thereby reducing the SERS intensity. The test strips were designed to be highly specific and reproducible, and the entire assay was completed in 15 minutes. The test strips we designed were simpler, more sensitive, and more efficient than other detection methods. The detection limit in serum were 21.14 fM for miR-19a-3p and 10.34 fM for miR-4491. In addition, the results of SERS-based LFA test strip and quantitative real-time polymerase chain reaction (qRT-PCR) were consistent for serum testing of healthy individuals, patients with mild intraepithelial neoplasia (IE), patients with severe IE, and patients with gastric cancer. Therefore, SERS-based LFA test strip has great potential for the clinical diagnosis of gastric cancer.