title: Detection of Hg2+ and F- ions by using fluorescence switching of quantum dots in an Au-cluster-CdTe QD nanocomposite.
abstract: A single probe of an Au nanocluster-CdTe quantum dots nanocomposite has been developed by using tripeptide-capped CdTe quantum dots (QD) and bovine serum albumin (BSA) protein-conjugated Au25 nanocluster (NC) for detection of both Hg(2+) ion and F(-) ion. The formation of Au-NC-CdTe QD nanocomposite has been confirmed by TEM, steady state and time resolved spectroscopy, CD and FTIR studies. A significant signal off (74 % PL quenching at 553 nm) phenomenon of this nanocomposite is observed in presence of 6.56×10(-7)  M Hg(2+) ion, due to salt-induced aggregation. However, a dramatic PL enhancement (128 %) of the Au-NC-CdTe QD nanocomposite is observed in presence of 8.47×10(-7)  M F(-) anion. The calculated limit of detections (LOD) of Hg(2+) ion concentration and F(-) ion concentration are found to be 9 and 117 nM, respectively, which are within the safety range set by the United States Environment Protection Agency. Thus, the simple Au-NC-CdTe QD optical-based sensor is very useful to detect both toxic cations and anions.
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata 700 032, India.
authors.forename: Bipattaran
authors.initials: B
authors.lastname: Paramanik
authors.forename: Santanu
authors.initials: S
authors.lastname: Bhattacharyya
authors.forename: Amitava
authors.initials: A
authors.lastname: Patra
mesh_terms: D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry*; D002417:Cattle; D005453:Fluorescence; D005459:Fluorides / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D057230:Limit of Detection; D008628:Mercury / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013691:Tellurium / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D007477:Ions; D012710:Serum Albumin, Bovine; D006046:Gold; D008628:Mercury; D013691:Tellurium; D005459:Fluorides