Monitoring layer-by-layer self-assembly process of natural polyelectrolytes by fluorescent bioconjugate with aggregation-induced emission characteristic.

A novel chitosan-based fluorescent bioconjugate (TPE-CS) with aggregation-induced emission (AIE) characteristic is synthesized and used as a fluorescent probe for monitoring layer-by-layer self-assembly process of natural polyelectrolytes. QCM results and contact angle measurement indicate that this AIE active TPE-CS bioconjugate can be assembled with alginate (ALG) through layer-by-layer deposition. Ellipsometry and fluorescence (FL) spectroscopy show an exponential growth of the TPE-CS/ALG multilayer films. Moreover, the exponential relationship between the FL intensity and the number of bilayers, which is in accordance with the thickness variation of multilayer films, provides solid evidence for its capacity to monitor the layer-by-layer self-assembly process.