Fluorescent dye-doped silica nanoparticles (FSNs) with gold nanoparticle (Au NP) seeds are synthesized for a fluorescence-based solid-phase detection of target chemicals based on the growth of Au NPs. The FSN-Au NP probe was successfully applied to the detection of H(2)O(2), hydroquinone, glucose, acetylthiocholine, and neurotoxin by employing glucose oxidase and acetylcholine esterase.