PREPARATION OF SILICA-COATED MAGNETIC NANOPARTICLES FUNCTIONALIZED WITH GLUCOSE

Abstract

The silica is well-known for the biocompatible material, and has the silanol groups at the end which make various ligands attach to its surface. So, the silica whose surface is functionalized with glucose can be applied to the biomedical techniques, for example, imaging techniques, because glucose is essentially required to the metabolism process. In addition, because of the magnetic nanoparticles which are embedded in silica particles, the collection of used nanocomposites is possible. Eventually, the purpose of this research is to prepare the silica-coated magnetic nanoparticles and functionalize them with glucose molecules. The silica-coated magnetic nanoparticles are synthesized in two stages. First, Fe3O4 magnetic nanoparticles are made by co-precipitation method, which uses FeCl2, FeCl3 and base catalyst, NH4OH. These particles have superparamagnetic behaviour, so the aggregation occurs spontaneously. To prevent them from aggregation, second stage is required. In second stage, we use sol-gel method to obtain silica-coated magnetic particles. TEOS is employed as the precursor material of silica. Because of high affinity between silica and magnetite surface, it is possible to encapsulate magnetic particles with silica directly. In this stage, ethanol and water are used as solvent, and the catalyst is NH4OH. From the surface of Fe3O4 particles, the growth of the silica particles occurs and we can obtain magnetite-silica nanocomposites. After this process, silica particles in which a few magnetic particles are embedded have to be treated with the functional groups, for example, amine groups, to make the glucose molecules attach easily. Next, the glucose molecules are adsorbed to the silica surfaces by the interaction between amine groups of the silica surface and the hydroxide groups of the glucose. The introduction of magnetic nanoparticles into the silica particles are confirmed by transmission electron microscope (TEM). Magnetic property of the products is measured by vibrating sample magnetometer (VSM). In order to test the chemical bonding between the silica and glucose, we use Infrared microscopy (IR).