Intrinsically fluorescent and quercetin loaded highly crosslinked polyphosphazene nanospheres: synthesis, characterization and fluorescence properties.

Highly crosslinked, inorganic-organic hybrid and intrinsically fluorescent polyphosphazene nanospheres bearing hydroxyl groups on the surface are facilely generated via a one-pot polycondensation of octachlorocyclotetraphosphazene, fluorescein and quercetin. The resulting nanospheres were characterised by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), X-ray diffraction analysis (XRD) and ultraviolet-visible spectroscopy (UV-vis) techniques. The average diameter of the nanospheres was determined as 379 nm. Also, quercetin which is both a monomer and an anticancer drug was loaded to the nanospheres as 446 mg g. The obtained nanospheres possess outstanding disperse ability in both aqueous and organic solvents. Moreover, the nanospheres exhibited intrinsically fluorescence intensity and outstanding photobleaching stability under ultraviolet-visible irradiation, due to the highly crosslinked and inorganic-organic hybrid structure. Owing to these superior properties and novelty of synthesized nanospheres, they have a great potential in many applications such as fluorescent labels, sensors, cell imaging and as a nanocarrier of quercetin for cancer treatment.