Ratiometric and sensitive cyanide sensing using dual-emissive gold nanoclusters.

The detection of cyanide anion (CN), a highly toxic pollutant, has attracted growing attention in the past years. In this work, a nanosensor composed of hyperbranched polyethyleneimine (hPEI)-assisted dual-emissive gold nanoclusters (DE-Au NCs) is proposed for ratiometric detection of CN based on surface valence state-driving etch. The ratiometric color change of fluorescence is based on a fact that the red-emissive Au NCs with a high content of surface Au(I) can be easily etched by CN, while the blue-emissive Au NCs with nearly neutral character can resist CN.

A Eu-inspired fluorescent carbon nanodot probe for the sensitive visualization of anthrax biomarker by integrating EDTA chelation.

The rapid and sensitive visualization of 2,6-dipicolinic acid (DPA, a unique anthrax biomarker) is essential to prevent anthrax disease or biological terrorist attack. In this study, a Eu-labeled ethylenediaminetetraacetic acid loaded hyperbranched polyethyleneimine carbon nanodot (hPEI-CD-EDTA-Eu) nanoprobe has been proposed for the ratiometric DPA detection. The sensing mechanism is based on the rapid DPA-Eu chelation within 30 s and subsequent enhanced fluorescence emission through the antenna effect.