Ultrasensitive Au Nanooctahedron Micropinball Sensor for Mercury Ions.

Mercury ion (Hg2+) is one of the most toxic heavy metal which has severe adverse effects on environment and human organs even at very low concentrations. Therefore, highly sensitive and selective detection of Hg2+ is desirable. Here, we introduce plasmonic micropinball constructed from Au nanooctahedron as a 3D SERS platform, enabling ultrasensitive detection of trace Hg2+ ions. Typically, strong SERS signals could be obtained when the single-stranded DNA structure converts to the hairpin structure in the presence of Hg2+ ions, due to the formation of thymine (T)-Hg2+-T. As a result, the detection limit of Hg2+ ions is as low as 1 × 10-16 M, which is far below compared with these reported for conventional analytical strategies. Moreover, in order to achieve rapid multiple detection, we combine the micropinball sensors with microflow tube online detection. Our platform prevents cross-talk and tube contamination, allowing multi-assay analysis, rapid identification and quantification of different analytes and concentrations across separate phases.