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

氧化鐵磁性奈米粒子(Fe3O4 MNPs)以及二氧化矽包覆氧化鐵磁性奈米粒子(Fe3O4@SiO2 MNPs)在生醫方面漸漸變成很重要的應用，然而這種磁性奈米粒子對於細胞的影響仍然不是很清楚。因為表面修飾的氧化鐵磁性奈米粒子以及二氧化矽包覆氧化鐵磁性奈米粒子，其表面修飾物可能會在進入細胞時或是在細胞內被移除而形成裸露的氧化鐵磁性奈米粒子，因此裸露的氧化鐵磁性奈米粒子以及二氧化矽包覆氧化鐵磁性奈米粒子應該需要受到注意。在這個研究中，為了避免太多的前驅物殘留在奈米粒子上，氧化鐵磁性奈米粒子採用共沉降法來合成，而二氧化矽包覆氧化鐵磁性奈米粒子則利用Stober法合成。藉由X光繞射儀(XRD)、穿透式電子顯微鏡(TEM)、X光光電子能譜儀(XPS)、X光吸收光譜(XAS) 以及超導量子干涉磁量儀(SQUID)來量測這些磁性奈米粒子的性質以及特性，結果顯示合成的氧化鐵奈米粒子是以四氧化三鐵的相為主，而二氧化矽則是以非晶態沉積在氧化鐵奈米粒子上，這些合成的磁性奈米粒子都具有超順磁的特性。A549肺腺癌細胞被用來做為這些磁性奈米粒子處理的模式細胞，其細胞活性藉由MTT法檢測來取得。結果顯示經過磁性奈米粒子處理的A549細胞呈現出較低的粒線體還原酶活性。此外，同步輻射紅外光(SRIR)光譜以及同步輻射紅外光顯微鏡(SRIRM, 擁有10um 空間解析度)用來量測細胞內部的化學物質含量變化以及分布。結果顯示細胞內部的DNA結構間接地受到磁性奈米粒子的影響，其含量隨著磁性粒子的濃度增大以及作用時間而下降，雖然蛋白質以及磷脂質的結構沒有受到太大的影響，但它們的相對成分比例會隨著磁性奈米粒子作用的時間以及濃度，而有所不同;同時也可以觀察到暴露在磁性奈米粒子中A549細胞以及對造組A549細胞中，相對較多的蛋白質集中在核心，遠離核心的區域，磷脂質相對地比較多量。

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.