High sensitivity surface plasmon resonance biosensor for detection of microRNA based on gold nanoparticles-decorated molybdenum sulfide.

A high sensitive surface plasmon resonance (SPR) biosensor was proposed based on the gold nanoparticles-decorated molybdenum sulfide (AuNPs-MoS) for the first time. This SPR platform using the AuNPs-MoS nanocomposites as signal labels for the sensitive and facile measurement of microRNA (miRNA) was executed in only two steps. At first, the thiol-modified DNA oligonucleotide probes, including a sequence complementary to the target miRNA-141, were fixed on the Au film to identify the segment sequence of target miRNA-141. Then, the assistant DNA-linked AuNPs-MoS nanocomposites were used to combine with the other section of the miRNA-141. Performance of SPR biosensor was enhanced by taking advantage of the AuNPs-MoS nanocomposites, thus this newly presented sensing assay exhibited high sensitivity toward miRNA with a detection limit of 0.5 fM. Furthermore, the method showed high specificity, resulting in distinguishing differences among miRNA-200 family members. Especially, the assay could also be used to detect human miRNA from cancer cells, and the results were in excellent accord with the ones obtained using qRT-PCR. What is more, this presented method could be feasible for determining miRNA in 10% human serum. This assay may provide a great potential as a miRNA quantification method in complex samples, and exert significant effect on biomedical research and clinical early diagnosis.