A MICROEMULSION MEDIATED SYNTHESIS OF SUPERPARAMAGNETIC CORE-SHELL NANOPARTICLES FOR APPLICATION IN BIOMEDICINE

摘要

In recent years, monodisperse single-domain magnetic nanoparticles become more and more important in a wide range of biomedical applications, such as magnetic cell separations, therapeutic drug, gene and radionuclide delivery, hyperthermia treatments and MRI contrast enhancement. For reasons of biocompatibility, the present work was concentrated on the generally harmless maghemite (γ-Fe_2O_3) nanoparticles coated with a thin biocompatible layer of silica (SiO_2) shell in order to avoid the aggregation of nanoparticles and to provide their biocompatibility and resistance to physiological conditions. A precipitation in microemulsion system consisted of water / sodium n-dodecyl sulphate (SDS) / I-butanol / cyclohexane was used for the synthesis of γ-Fe_2O_3 nanoparticles. The influence of the microemulsions composition on the nature of the prepared γ-Fe_2O_3 nanoparticles were investigated. Further, surface coating of the prepared γ-Fe_2O_3 nanoparticles was proceeded through the pretentious stage of hydrolysis and condensation of tetraethoxysilane (TEOS) that was added to the microemulsion mixture after the formation of γ-Fe_2O_3 nanoparticles. Coated and uncoated magnetic (γ-Fe_2O_3) nanoparticles were characterized using transmission electron microscopy (TEM), X-ray diffractometry (XRD) and specific surface area measurements (BET). The specific magnetization (DSM-10, magneto-susceptometer) of the prepared samples was measured.