Fluorescent Beads Coated with Polyaniline: A Novel Nanomaterial for Optical Sensing of pH

A novel optical pH sensor for the physiological rangehas been developed by these authors. The fluorescence emitted (in a pH-independent manner) by dye-doped polymer nanobeads is modulated by a thin conductive polymer coating (see Figure), whose visible-light absorption strongly varies with pH at values around seven.