Metal enhanced fluorescence of the fluorescent brightening agent Tinopal-CBX near silver island film

Metal-enhanced fluorescence (MEF) studies of the optical brightener Tinopal-CBS (4,4'-distyrylbiphenyl sulfonic sodium salt) have been undertaken using steady-state and time resolved fluorescence measurements on silver island films (SiFs) deposited on glass slides and silver nano-particles adsorbed onto cellulose based filter paper. Nearly a 4.5 fold enhancement in fluorescence intensity is observed from both SiFs and nano-particle deposited cellulose filter paper. In addition an enhanced photostability and decrease in decay time is also observed on SiFs. These results are consistent with two distinct mechanisms of MEF, firstly coupling and transferring of the excited states energies of fluorophores to surface plasmons in the silver island deposited glass films, and secondly, an electric field enhancement effect, which facilitates enhanced absorption of the fluorophores. Our findings reveal significant benefits of enhanced luminescence and prolonged photostability of Tinopal CBS. As such, Plasmon-tinopal constructs offer new material opportunities as well as multifarious applications in the life sciences. (C) 2011 Elsevier Ltd. All rights reserved.