Abstract: Three generations of magnetic and luminescent dendrimer microspheres were prepared. Superparamagnetic Fe₃O₄ nanoparticles were first prepared by hydrothermal coprecipitation of ferric and ferrous ions, followed by the modification of their surfaces with dendrimers. The surface-modified Fe₃O₄ nanoparticles were then linked to CdSe/CdS quantum dots(QDs), which were modified with thioglycolic acid to form the Fe₃O₄/CdSe/CdS fluorescent magnetic nanocomposites through the adsorption and bonding of the amino groups on the surfaces of Fe₃O₄ and the carboxyl groups on CdSe/CdS QDs. The structure and properties of the nanocompo-sites were characterized by Fourier transform infrared spectrometer(FTIR), elemental analysis(EA), transmission electron microscope(TEM), energy dispersive spectrometer(EDS), vibrating sample magnetometer(VSM), photoluminescence(PL) and UV-Vis spectrameters. The results show that the average size of three generations of nanocomposites are 15, 34 and 49 nm, respectively, the fluorescence property of G1F is the best with a fluorescent quantum yield up to 24.1%, while the magnetic property of G0F is the optimal with a saturation magnetization of 15.96 A穖²/kg. The synthesized bifunctional nanocomposites are expected to be widely used in immune detection, luminescence detection, targeted therapy, magnetic separation and so on.

Key words: Fluorescence, Magnetic property, Dendrimer, Nanoparticles