Advances　in　the　controlled　assembly　of　nanoscale　building　blocks　have　resulted　in　functional　devices　which　can　find　applications　in　electronics,　biomedical　imaging,　drug　delivery　etc.　In　this　study,　novel　covalent　nanohybrid　materials　based　upon　[Ru(bpy)3]2+-doped　silica　nanoparticles　(SiNPs)　and　gold　nanoparticles　(AuNPs),　which　could　be　conditioned　as　OFF-ON　probes　for　glutathione　(GSH)　detection,　were　designed　and　assembled　in　sequence,　with　the　disulfide　bonds　as　the　bridging　elements.　The　structural　and　optical　properties　of　the　nanohybrid　architectures　were　characterized　using　transmission　electron　microscopy,　UV-vis　spectroscopy　and　fluorescence　spectroscopy,　respectively.　Zeta　potential　measurements,　x-ray　photoelectron　spectroscopy　and　Fourier　transform　infrared　spectroscopy　were　employed　to　monitor　the　reaction　processes　of　the　SiNPs-S-S-COOH　and　SiNPs-S-S-AuNPs　synthesis.　It　was　found　that　the　covalent　nanohybrid　architectures　were　fluorescently　dark　(OFF　state),　indicating　that　SiNPs　were　effectively　quenched　by　AuNPs.　The　fluorescence　of　the　OFF-ON　probe　was　resumed　(ON　state)　when　the　bridge　of　the　disulfide　bond　was　cleaved　by　reducing　reagents　such　as　GSH.　This　work　provides　a　new　platform　and　strategy　for　GSH　detection　using　covalent　nanohybrid　materials.　©　2013　IOP　Publishing　Ltd.