Abstract
A new ligand of 4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid (DPPDA) and Eu3+chelate compound of this ligand were prepared. Then DPPDA-Eu3+ doped silica fluorescent nanoparticles of DPPDA-Eu3+/SiO2 with primary amino groups on their surface were developed using a water-in-oil (W/O) microemulsion technique. Characterizations by transmission electron microscopy, fluorescent spectra, fluorescent molecules leaking experiments and photostable experiments show that the nanoparticles are spherical, monodisperse, and uniform in size (80±8 nm in diameter). The nanoparticles have high fluorescent signal and high photostability. When the nanoparticles were dispersed in aqueous solution with continuously ultrasound for 4 h, no obvious leakage of fluorescent molecules were observed. As a novel fluorescent probe, the nanoparticles are expected to be applied in highly sensitive bioassays systems such as time-resolved fluorescence immunoassay, biosensor and biochip.
