Fluorescent reagent sodium 1-naphthylamine diacetate was assembled onto quartz wafer surface via its electrostatic interaction with cysteine that was directly assembled on gold nanoparticles adsorbed at quartz surface. Formation of the self-assembled bilayers was confirmed and primarily characterized by absorption and fluorescence spectra. Strong fluorescence was observed from the quartz surface and was found highly efficiently quenched by Cu2+ that allowed for a highly sensitive detection of Cu2+. (C) 2007 Published by Elsevier B.V.