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Preparation, characterization, and utilization of multi-functional magnetic-fluorescent composites for bio-imaging and magnetic hyperthermia therapy
- Rittikulsittichai, Supparesk, Singhana, Burapol, Bryan, William W., Sarangi, Subhasis, Jamison, Andrew C., Brazdeikis, Audrius, Lee, T. Randall
- RSC advances 2013 v.3 no.21 pp. 7838-7849
- aqueous solutions, encapsulation, fever, fluorescein, fluorescence, fluorescence emission spectroscopy, image analysis, magnetic properties, magnetism, nanocomposites, nanoparticles, pH, rhodamines, scanning electron microscopy, silica, therapeutics, transmission electron microscopy, umbelliferones
- This paper describes the synthesis, characterization, and utilization of unique multi-functional magnetic composites that integrate optical and magnetic properties in a single structure for use in hyperthermia therapy, and magnetic and fluorescence imaging. The composites are comprised of nanoscale magnetic core particles that are encapsulated by a silica layer that contains covalently-embedded organic dyes. The morphologies of the nanocomposite particles were characterized by TEM and FE-SEM. Their optical and magnetic properties were evaluated by spectrofluorometry and SQUID magnetometry, respectively. The results demonstrate that the nanocomposites are monodisperse and uniformly spherical with well-defined shell–core structures; moreover, they exhibit high magnetic saturation, produce vivid fluorescence, and can be designed to provide exceptional stability in aqueous solution over a wide range of pH and at elevated temperatures. For the three dyes utilized in the synthesis of these composites, rhodamine B (RhB), fluorescein (Flu), and 7-hydroxycoumarin (Cou), the observed relative stability for the nanoparticles was: RhB-SiO₂–Fe₃O₄ > Flu-SiO₂–Fe₃O₄ > Cou-SiO₂–Fe₃O₄. Additionally, potential uses of these composite nanoparticles as bimodal contrast agents and therapeutic entities are demonstrated.