Synthesis and Characterization of Ratiometric, pH Sensing Nanoparticles with Covalently Attached Fluorescent Dyes

Abstract

Polyacrylamide-based, ratiometric pH nanosensor particles with a mean diameter of 50 nm were prepared by microemulsion polymerization. A pH sensitive dye, a fluoresceinamine derivative, and a pH insensitive reference dye, a rhodamine B derivative, were covalently linked to the nanoparticle matrix by copolymerization to provide a stable and robust nanosensor. The dyes are distributed throughout the matrix.