利用同步輻射紅外光分析 Fe 3 O 4 和 Fe 3 O 4 @SiO 2 奈米材料對人類肺腺癌活細胞的影響

Abstract

Fe3O4 and Fe3O4@SiO2 magnetic nanoparticles (MNPs) have recently become important in biomedical applications; however, influences of these MNPs to cells are still not very clear. Bare Fe3O4 and Fe3O4@SiO2 MNPs should be noticed because any surface modification may be removed from them when they enter into cells or in cells. In this work, in order to avoid too much surface residues from the precursors, coprecipitation method is adopted to synthesize bare Fe3O4 MNPs, while Stober process is performed to synthesize bare Fe3O4@SiO2 MNPs. The characterization of MNPs is indentified by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Spectroscopy (XAS) and Superconducting Quantum Interference Device Magnetometer (SQUID). These results show that as-prepared Fe3O4 MNPs primarily contains crystalline Fe3O4 phase, while the deposited SiO2 on Fe3O4 MNPs is amorphous. A549 lung cancer cells are used as model cells for MNPs treatment, and the cell viability is measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results show that mitochondrial reductase activity in cells is reduced by treating Fe3O4 MNPs and Fe3O4@SiO2 MNPs to A549 cells for 36 hr. Instead of traditional biochemical methods, synchrotron radiation infrared-ray (SRIR) spectra and synchrotron radiation infrared-ray microscopy (SRIRM) with high spatial resolution 10μm are carried out to measure the change of chemical components and chemical composition distribution in cells. These results exhibit that DNA structures in cells are indirectly affected by Fe3O4 MNPs and Fe3O4@SiO2 MNPs, and the concentration of DNA becomes less with MNPs concentration and treatment time while no protein and lipid changes are observed, but the lipid/protein ratio is MNPs-concentration-dependent and treatment-time-dependent and it is observed that the amount of lipids is relatively larger at far-nucleus regions while that of proteins is relative larger at and around the nucleus region.