▎ 摘　　要

A versatile and sensitive surface plasmon resonance (SPR) biosensor based on two layers of graphene oxide-gold nanoparticles (GO-AuNPs) composites was designed for the detection of microRNA (miRNA) and small molecule adenosine. The bottom layer, which acted as a functionalized substrate on the sensor chip, provided a high specific surface area convenient for the immobilization of capture DNA molecules. The upper layer served as a signal-amplification element. By employing these two layers of GO-AuNPs composites, the dual amplification strategy was achieved so that a measurement of miRNA-141 with a detection limit of 0.1 fM was obtained. Moreover, the developed SPR biosensor showed decent selectivity toward miRNA-200 family members. Especially, the SPR biosensor demonstrated its applicability for the detection of miRNA-141 in cancer cell extractions, and the results obtained were consistent with those obtained by qRT-PCR. Interestingly, small molecule adenosine could also be detected using this SPR biosensor in combination with a split aptamer. Considering the superior sensitivity, selectivity and generality, this work promised much potential for the detection of various biomolecules.