A core-shell-type fluorescent nanosphere possessing reactive poly(ethylene glycol) tethered chains on the surface for zeptomole detection of protein in time-resolved fluorometric immunoassay - Hoshino, Nobuhiro.; Kataoka, Kazunori.; Matsuya, Takeshi.; Nagasaki, Yukio.; Shibata, Naoya.; Tashiro, Shigeru.