Fabrication of fluorescent chitosan-containing microcapsules

Intense emission peaks of Eu(DBM) 3 Phen (DBM and Phen are dibenzoylmethane and 1,10-phenanthroline, respectively) in the microcapsules containing molecules of quaternary ammonium chitosan (QACS) and sodium alginate are observed. The microcapsules are assembled by using CaCO3 particles as template cores by the layer-by-layer (LbL) technique. Observation of microcapsules by the fluorescence mode and the transmission mode in the confocal laser scanning microscopy shows that the microcapsules are intact after core decomposition. Fluorescence under ultraviolet irradiation comes directly from the Eu(DBM) 3 Phen. Homogeneous assembly of Eu(DBM) 3 Phen can be deduced due to the homogeneous fluorescence of the microcapsules in the fluorescence micrographs. The microcapsules show adherence to solid substrates due to large quantities of hydroxyl groups of QACS. AFM measurements of dried hollow microcapsules with only 4 bilayers of (CS/SA) fabricated with Eu(DBM) 3 Phen show the intact shell with a thickness of 3.0 nm. Regarding the biocompatible natural polysaccharides and the intense fluorescence emission, the microcapsules in this work might be of great importance in potential application in drug delivery and bioassay.