Recyclable sensitive fluorimetric detection of specific metal ions using a functionalized PEG-PS resin with a fluorescent peptide sensor

Previously, we synthesized a fluorescent peptide sensor consisting of heptapeptide for Cu(II) and Zn(II) ions, respectively. The peptide sensor detected Cu(II) ions by turn off response and Zn(II) ions by turn on response among 13 metal ions in aqueous solutions. In the present study, we prepared a functionalized resin by immobilization of the fluorescent peptide sensor into PEG-PS resin beads and investigated the sensing ability for the metal ions in aqueous solutions. The functionalized resin was easily used for detecting heavy metal ions in aqueous solutions using spectrofluorometer with stirrer. The functionalized resin with the peptide sensor showed a selective response to Cu(II) and Zn(II) ions among 13 metal ions in aqueous solutions. The functionalized resin with the peptide sensor, showed a turn off response to Cu(II) and a turn on response to Zn(II) ions in aqueous solutions. The resin showed a very sensitive response to Cu(II) and Zn(II) ions; about 1 equiv of the metal ions was enough to saturate the fluorescent change of the resin. Furthermore, the recycle of the resin bead for detecting metal ions was demonstrated by simply washing of the resin with EDTA solution and fluorescent response for Cu(II) ions.