title: Fluorescence modulation of acridine and coumarin dyes by silver nanoparticles.
abstract: Silver nanoparticles were synthesized by chemical reduction of silver ions by sodium borohydride in the presence of poly-(N)-vinyl-2-pyrrolidone in solution of short chain alcohols. The nanoparticles are stable in 2-propanol, and the average diameter of the Ag colloid obtained in this solvent is about 6 nm. The photophysical properties of acridinium and coumarin dyes in 2-propanol are affected by the presence of silver nanoparticles. The interaction of silver nanoparticles with acridinium derivative leads to a spectral change of its intramolecular charge transfer (ICT) absorption band. The dye emission increases suddenly with the initial addition of the Ag metal nanoparticles, but at a high concentration of the colloid, static fluorescence quenching occurs with a progressive decrease of the fluorescence efficiency. Amino coumarin fluorescence is only quenched by the silver nanoparticles in solution.
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, 13566-590, São Carlos, SP, Brazil.
authors.forename: Carolina A
authors.initials: CA
authors.lastname: Sabatini
authors.forename: Robson V
authors.initials: RV
authors.lastname: Pereira
authors.forename: Marcelo H
authors.initials: MH
authors.lastname: Gehlen
mesh_terms: D019840:2-Propanol; D000166:Acridines / Q000737:chemistry*; D003374:Coumarins / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: D000166:Acridines; D003374:Coumarins; D005456:Fluorescent Dyes; D012996:Solutions; D012834:Silver; D019840:2-Propanol