Entrapment of organic fluorophores in calcium phosphate nanoparticles with slow release

Abstract

Two organic fluorophores, fluorescein (F) and rhodamine B (Rd), were entrapped in calcium phosphatenanoparticles. The as-obtained nanoparticles can be used for biological release applications. For this aim, calciumphosphate nanoparticles were synthesized using the precipitation method. Structural analysis of these nanoparticles wasperformed using XRD, FTIR, and Raman spectroscopy, confirming that the synthesized nanoparticles were hydroxyapatite. TEM and SEM analyses demonstrated that these nanoparticles had a size of 20 nm and a well-defined morphology.F and Rd (about 0.5 wt.%) were entrapped in these nanoparticles and their release, as a function of time, was studiedvia UV-Vis spectroscopy. The obtained results showed that the release of both fluorophores was progressive over time.The trapping efficiencies of the fluorophores were 67.15% and 90.76% for F and Rd, respectively.