Patent ID: 7390462

Claim:
A ratiometric fluorescent pH sensor comprising: a fluorescent dye immobilized within a polymer matrix comprising, 6-methacryloyl-8-hydroxy-1,3-pyrene disulfonic acid (MA-HPDS) covalently bound within a p(ethylene glycol) hydrogel matrix; or 8-hydroxy,1,3,6-pyrene trisulphonic acid trisodium salt (HPTS) ionically bound within a p(ethylene glycol) diacrylate monomer that is polymerized around an anionic exchange resin; said fluorescent dye exhibiting a shift in excitation wavelength with a corresponding shift in pH in the local environment of said fluorescent dye and said polymer matrix comprising a front surface and a back surface; a siloxane-based comonomer; embedded in the polymer matrix, a means of optically isolating said polymer matrix comprising said fluorescent dye; and an adhesive means on the front surface of the polymer matrix.