Preparation and Characterization of Bimodal Magnetofluorescent Nanoprobes for Biomedical Application

Magnetic-fluorescent bifunctional Fe₃O₄/SiO₂-CdTeS nanocomposites are synthesized. Fe₃O₄ superparamagnetic nanoparticles are firstly prepared through the thermal decomposition of Fe oleate precursors and coated with a mesoporous silica shell using the St?ber method, and the silica surface is then modified with positively charged amino groups by adding 3-aminopropyltrimethoxysilane. Finally, negatively charged CdTeS quantum dots are linked and assembled onto the positively charged surface of Fe₃O₄/SiO₂ through electrostatic interactions. X-ray diffraction, transmission electron microscopy, photoluminescence spectroscopy, and magnetometry are applied to characterize the nanocomposites. The results show that the bifunctional nanocomposites combine the optical properties of near-infrared CdTeS quantum dots with the superparamagnetic properties of Fe₃O₄ perfectly, expressing the potential application as a biocompatible magnetofuorescent nanoprobe for in vivo labelling.