Synthesis and Characterization of Chitosan-Based Polyelectrolyte Complexes Doped with Xanthene Dyes

Biocompatible chitosan-based polyelectrolyte complexes (PECs) doped with xanthene dyes (fluorescein, eosinY, erythrosinB, rhodamine6G) were synthesized and characterized by scanning electron microscopy, dynamic light scattering, zeta potential measurements, and absorption and luminescence (including polarized, time-resolved, and phosphorescence) spectroscopy. The results are discussed in terms of the mechanism and rigidity of dye-PEC binding, the heavy-atom effect in dyes and PEC stability. EosinY is found to be the optimal dopant, providing both a high dye content in PECs and a high quantum yield of fluorescence.