Facile synthesis of inorganic-organic hybrid fluorescent nanoparticles with AIE feature using hexachlorocyclotriphosphazene as the bridge

In recent 20 years, the functional materials with aggregation-induced emission (ALE) feature have shown huge superiority and great potential in biomedicine field and numerous strategies have been developed to fabricate these ALE-active functional materials. Though delightful developments, facile synthesis of inorganic-organic hybrid fluorescent nanoparticles with AIE feature has seldom reported thus far. In this work, we reported for the first time that novel cross-linked inorganic-organic hybrid polyphosphazene nanospheres with AIE feature could be simply synthesized via conjugation ALE-active fluorophore tetraphenylethylene derivative (TPE-NH 2 ) with hydrophilic polyethylene glycol (PEG-NH2) using hexachlorocyclotriphosphazene (HCCP) as the bridge. This strategy is simple and high-efficient with some advantages (e.g., the reaction can occur under room temperature, the reaction time is short, no surfactant is required and no air-protection is needed). The structure, morphology and spectroscopic properties of TPE-HCCP-PEG nanoparticles (NPs) were characterized by various apparatus. To further evaluate their potential applications in biomedical fields, biocompatibility and cell uptake behavior of TPE-HCCP-PEG composites have been examined. Results demonstrated that TPE-HCCP-PEG NPs possessed intensive fluorescence and high water dispersibility and were of low cytotoxicity. These features endow TPE-HCCP-PEG NPs huge potential in fluorescence imaging. Also, the strategy can be extended for the construction of many other inorganic-organic hybrid polymers taken advantage of their unique features and convenient synthetic method. We expect that this work will open a new avenue for the synthesis of inorganic heterocycles centered ALE-active materials with extensive application prospects. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study reports a simple and efficient method to synthesize inorganic-organic hybrid polyphosphazene nanospheres with aggregation-induced emission (ALE) feature by conjugating ALE-active fluorophore with polymer. The resulting nanoparticles exhibit intense fluorescence, high water dispersibility, and low cytotoxicity, showing great potential in fluorescence imaging. This strategy can be further extended to construct various other inorganic-organic hybrid polymers for diverse applications.