One-pot synthesis of fluorescent and cross-linked polyphosphazene nanoparticles for highly sensitive and selective detection of dopamine in body fluids

摘要

Highly cross-linked and monodisperse polyphosphazene (PZS) nanoparticles exhibiting strong fluorescence were prepared by the facile one-pot polycondensation of hexachlorocyclotriphosphazene and 4',5'-dibromofluorescein (DBF). Fluorescent DBF units were 'immobilized' and 'isolated' in the crosslinked structures to effectively overcome their concentration-quenching effect and improve their photobleaching properties. The resulting DBF-PZS nanoparticles emitted bright yellow fluorescence at all concentrations and exhibited excellent resistance to photobleaching as well as interference from biomolecules such as proteins, ascorbic acid and uric acid. Intriguingly, the fluorescence of the DBF-PZS nanoparticles was linearly quenched by DA in the range of 0.5 to 15 mu g mL(-1) DA concentration via photoinduced charge transfer. Therefore, the use of DBF-PZS nanoparticles represents a simple but effective, highly sensitive and selective detection method with a direct read out for DA in biological fluids.