The hydroxyl groups of poly(tert-butyl acrylate)-block-poly(2-hydroxyethyl methacrylate) or PtBA-b-PHEMA were reacted with succinic anhydride to introduce some carboxyl groups into the PHEMA block. Such carboxyl groups were then reacted with Texas-red cadverine (TX-NH(2)) to incorporate dye molecules. The TX-bearing diblocks formed probably spherical micelles in block-selective solvent DMF/toluene containing 2% DMF. "Permanent" micelles or nanospheres were prepared after cross-linking the TX-bearing PHEMA core block. Such nanospheres were made water soluble by cleaving the tert-butyl groups from the PtBA coronas. Water-soluble nanospheres with high TX numbers and fluorescence quantum yields may find applications in fluorescence in situ hybridization assays.