title: Approaching sensitivity of tens of ions using atomically precise cluster-nanofiber composites.
abstract: A new methodology has been demonstrated for ultratrace detection of Hg(2+), working at the limit of a few tens of metal ions. Bright, red luminescent atomically precise gold clusters, Au@BSA (BSA, bovine serum albumin), coated on Nylon-6 nanofibers were used for these measurements. A green emitting fluorophore, FITC (fluorescein isothiocyanate), whose luminescence is insensitive to Hg(2+) was precoated on the fiber. Exposure to mercury quenched the red emission completely, and the green emission of the fiber appeared which was observed under dark field fluorescence microscopy. For the sensing experiment at the limit of sensitivity, we have used individual nanofibers. Quenching due to Hg(2+) ions was fast and uniform. Adaptation of such sensors to pH paper-like test-strips would make affordable water quality sensors at ultralow concentrations a reality.
authors.affiliation: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras , Chennai 600 036, India.
authors.forename: Atanu
authors.initials: A
authors.lastname: Ghosh
authors.forename: Vedhakkani
authors.initials: V
authors.lastname: Jeseentharani
authors.forename: Mohd Azhardin
authors.initials: MA
authors.lastname: Ganayee
authors.forename: Rani Gopalakrishnan
authors.initials: RG
authors.lastname: Hemalatha
authors.forename: Kamalesh
authors.initials: K
authors.lastname: Chaudhari
authors.forename: Cherianath
authors.initials: C
authors.lastname: Vijayan
authors.forename: Thalappil
authors.initials: T
authors.lastname: Pradeep