A fluorimetric testing strip for the visual evaluation of mercury in blood using copper nanoclusters with DMSO-enhanced fluorescence and stability

A fluorimetric analytical method using test strips has been fabricated for detecting Hg 2+ ions in blood by using copper nanoclusters (Cu NCs) prepared via a biomineralization route. Unexpectedly, the as-prepared Cu NCs displayed greatly amplified red fluorescence once dispersed in DMSO, the intensity of which decreased specifically in the presence of Hg 2+ . Moreover, the resultant Cu NCs were deposited onto test strips to be further fast dried on superhydrophobic substrates in vacuum. The test strip-based fluorimetry can allow for the direct analysis of Hg 2+ in blood in the linear concentration range of 0.10-1000 nM. Importantly, this solvent-enhanced fluorescence protocol for different metal probes such as Cu NCs promises extensive analysis applications for designing numerous fluorimetric platforms such as test strips. Copper nanoclusters with DMSO-enhanced red fluorescence were coated onto test strips for the fluorimetric evaluation of Hg 2+ by triggering the fluorescence quenching.