title: "Stainless" Gold Nanorods: Preserving Shape, Optical Properties, and SERS Activity in Oxidative Environment.
abstract: One of the main limitations to the application of gold nanorods (Au NRs) as surface-enhanced Raman scattering (SERS) probes for in situ monitoring of chemical processes is their instability in oxidative environments. Oxidation induces progressive anisotropic shortening of the NRs, which are eventually dissolved once this process has been completed. This paper compares two types of Au NRs, obtained through different routes and characterized by similar aspect ratios but different sizes. The key factors influencing the resistance of Au NRs to oxidation were systematically investigated, showing that the reduction of free bromide species and the increase of the particle size allowed the NRs to maintain their stability under harsh environments for several weeks. The most stable Au NRs were also demonstrated to be highly efficient SERS substrates in a series of Raman experiments involving molecular probes, treated under either oxidizing or nonoxidizing conditions, which simulate the oxidation of organic pollutants in water. These hallmarks make these "stainless" Au NRs attractive tools for ultrasensitive diagnostic under real working conditions.
authors.affiliation: INSTM and Chemistry for Technologies Laboratory, Mechanical and Industrial Department, University of Brescia , Via Branze 38, 25123 Brescia, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Vassalini
authors.affiliation: IMEM-CNR , Parco Area delle Scienze 37/A, 43124 Parma, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Rotunno
authors.affiliation: IMEM-CNR , Parco Area delle Scienze 37/A, 43124 Parma, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Lazzarini
authors.affiliation: INSTM and Chemistry for Technologies Laboratory, Mechanical and Industrial Department, University of Brescia , Via Branze 38, 25123 Brescia, Italy.
authors.forename: Ivano
authors.initials: I
authors.lastname: Alessandri
keywords: SERS; gold nanorods; in situ Raman; nanoparticle oxidation; organic pollutants; recyclable SERS materials