title: Rapid, selective, and ultrasensitive fluorimetric analysis of mercury and copper levels in blood using bimetallic gold-silver nanoclusters with "silver effect"-enhanced red fluorescence.
abstract: Bimetallic alloying gold-silver nanoclusters (Au-AgNCs) have been synthesized by a one-pot biomineralization synthesis route at a vital molar ratio of Au/Ag precursors in the protein matrix. Unexpectedly, the prepared Au-AgNCs could exhibit dramatically enhanced red fluorescence, which is about 6.5-fold and 4.7-fold higher than that of common AuNCs and core-shell Au@AgNCs, respectively. A rapid, selective, and ultrasensitive fluorimetric method has thereby been developed using Au-AgNCs as fluorescent probes toward the separate detections of Hg(2+) and Cu(2+) ions in blood. The interactions of Au-AgNCs with Hg(2+) and Cu(2+) ions were systematically characterized by microscopy imaging, UV-vis, and fluorescence measurements. It is demonstrated that the "silver effect" gives the Au-AgNCs probes not only greatly enhanced red fluorescence but also the strong capacity to specifically sense Cu(2+) ions in addition to improved response to Hg(2+) ions. Moreover, aided by a Cu(2+) chelating agent, exclusive detection of Hg(2+) ions could also be expected with the coexistence of a high level of Cu(2+) ions, as well as reversible Cu(2+) analysis by restoring the fluorescence of Au-AgNCs. Additionally, Au-AgNCs with strong red fluorescence could facilitate fluorimetric analysis with minimal interference from blood backgrounds. Such an Au-AgNCs-based fluorimetric method can allow for the selective analysis of Hg(2+) and Cu(2+) ions down to 0.30 nM and 0.60 nM in blood, respectively, promising a novel detection method to be applied in the clinical laboratory.
authors.affiliation: Shandong Province Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University , Qufu City, Shandong 273165, P. R. China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Si
authors.forename: Zongzhao
authors.initials: Z
authors.lastname: Sun
authors.forename: Lijun
authors.initials: L
authors.lastname: Chen
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Yuchun
authors.initials: Y
authors.lastname: Qiao
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
mesh_terms: D003300:Copper / Q000097:blood*; D005453:Fluorescence; D005470:Fluorometry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008628:Mercury / Q000097:blood*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver; D006046:Gold; D003300:Copper; D008628:Mercury