Colorimetric/fluorescent/Raman trimodal sensing of zinc ions with complexation-mediated Au nanorod

Accurate and selective in-field detection of metal ions in complex media has gained wide interests due to the complexed matrices and weak affinity towards sensing surface. Herein, we develop a first trimodal method for sensing of Zn2+ in complex matrices by stimuli-responsive N-[6-piperazinyl-2-pyridinyl]-N-(2-pyridinylmethyl)-2-Pyridinemethanamine dithiocarbamates (DPY) modified gold nanorods (GNRs-DPY). The presence of Zn2+ triggers the aggregation of GNRs-DPY, leading to increment of color and fluorescence intensity of the sensing system, which could be visually discerned with bare eye. Moreover, the intensive electromagnetic enhancement among "hot spots" of GNRs, generated during self-aggregation of the GNRs-DPY caused by Zn2+, lowers the detection limit of SERS assay to 6 x 10(-3) pM. It is noteworthy that GNRs-DPY based sensing platform not only enables distinguishing Zn2+ from Cd2+, with simplicity and rapidity, but also demonstrates as trimodal nanoprobe for sensitive and selective quantitative determination of Zn2+ in different matrices. Therefore, the GNRsDPY provides a new strategy for accurate and credible on-spot determination of Zn2+ in complicated specimens, as well as offering multiple applications in point-of-care monitoring.