title: Self-organized fluorescent nanosensors for ratiometric Pb2+ detection.
abstract: Silica nanoparticles (60 nm diameter) doped with fluorescent dyes and functionalized on the surface with thiol groups have been proved to be efficient fluorescent chemosensors for Pb2+ ions. The particles can detect a 1 microM metal ion concentration with a good selectivity, suffering only interference from Cu2+ ions. Analyte binding sites are provided by the simple grafting of the thiol groups on the nanoparticles. Once bound to the particles surface, the Pb2+ ions quench the emission of the reporting dyes embedded. Sensor performances can be improved by taking advantage of the ease of production of multishell silica particles. On one hand, signaling units can be concentrated in the external shells, allowing a closer interaction with the surface-bound analyte. On the other, a second dye can be buried in the particle core, far enough from the surface to be unaffected by the Pb2+ ions, thus producing a reference signal. In this way, a ratiometric system is easily prepared by simple self-organization of the particle components.
authors.affiliation: Dipartimento di Scienze Chimiche and CNR-ITM, Università di Padova, via Marzolo 1, I -35131 Padova, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Arduini
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Mancin
authors.forename: Paolo
authors.initials: P
authors.lastname: Tecilla
authors.forename: Umberto
authors.initials: U
authors.lastname: Tonellato