MicroRNA detection using lateral flow nucleic acid strips with gold nanoparticles

In this study, the tested microRNA and the detection probe perfectly match with the capture probe instead of the traditional sandwich methods in which the tested oligonucleotide matches with the detection and capture probes. To avoid non-specific signals, mung-bean nuclease, a single-strand-specific nuclease, catalyzes the degradation of the capture probe if there is no tested miRNA in the samples. The gold nanoparticles conjugate the thiol-DNA as the detection probe and the biotin-single strand DNA serves as the capture probe. The avidin–biotin–Au-sample complex is captured by the anti-avidin antibody immobilized on a flow strip. The detection and quantification of the gold nanoparticle signal indicate the existence and quantity of the target miRNA. One fmol and five amol of the synthetic microRNA were detected without and with the silver enhancement, respectively. This highly sensitive and specific assay takes about 70 min after the RNA purification and preparation. It is simple, convenient, fast, and suitable for point-of-care.