Amphiphilic alginate-based fluorescent polymer nanoparticles: Fabrication and multifunctional applications

Alginate has been widely applied in various biological systems due to its great biocompatibility. Endowing it fluorescent imaging would make people to further understand its complex structure, process and mechanism. In this work, amphiphilic alginate conjugated with aggregation-induced emission (AIE) moiety fluorescent polymer was successfully fabricated through the Ugi one-pot condensation. The synthetic polymer particles were fully evaluated by various characterizations including ¹H NMR, FTIR, fluorescent spectroscopies, and transmission electron microscopy (TEM). These amphiphilic alginate particles showed great multicolor fluorescence emission in both solid and solution states. The corresponding biological evaluation results confirmed that the fluorescent biopolymer showed excellent biocompatibility and desirable bioimaging property. Particularly, the leaf stomata were directly visualized using the amphiphilic AIE-active alginate biopolymer. Furthermore, the alginate-based polymer can also be employed as the drug carrier for hydrophobic curcumin. These results indicated that our synthetic AIE-active alginate particles might provide great potential for the further utilization of alginate in the understanding of various relative biological systems.