Synthesis and Fluorescent Property of Biodegradable Polyphosphazene Targeting Long-Term in Vivo Tracking

Abstract

The importance of developing photoluminescent biodegradable scaffolding materials for tissue engineering is obvious, but it meets challenges with conventional biodegradable polymers such as aliphatic polyesters. In this study, photoluminescent biodegradable polyphosphazenes (PTA) were suggested as alternatives to target for long-term in vivo tracking applications. The PTA polymers were synthesized via nucleophilic cosubstitution of linear poly(dichlorophosphazene) with a fluorescent compound (TPCA) and alanine ethyl ester. The TPCA, with high fluorescent intensity and high quantum yield (∼0.5), was synthesized from citric acid and 2-aminoethanethiol. The resulted PTA polymers demonstrated adjustable degradation rates and fluorescent intensities in relating to their chemical compositions. In comparison with TPCA, the photostability of PTA polymers has been significantly improved, which made the long-term in vivo tracking feasible. PTA polymers were proven biocompatible and noncytotoxic for biomedical appli...