中文摘要：

为了研究不同表面修饰的磁性纳米粒子（MNPs）的细胞毒性作用，评价其生物安全性，选用小鼠成纤维细胞（L929），使用MTT比色法，对3-氨基丙基三乙氧基硅烷（APTS）修饰和溴化双十二烷基二甲基铵修饰的两种磁性纳米粒子不同剂量、时间对细胞的影响进行研究。结果发现，不同修饰的两种MNPs的浸提液的毒性分级试验中，APTS修饰的MNPs主要为1级，2级，合格；而高浓度DMAB修饰的MNPs的浸提液在48h组中为4级，有较强的毒性。MNPs的体外细胞毒性检测显示，APTS修饰的MNPs与DMAB修饰的MNPs相比，对细胞的生存率抑制较小。结果表明，APTS修饰的磁性纳米粒子生物相容性更好，磁性纳米粒子在不同剂量、时间对细胞毒性表现出一定的差异，存在一定程度的剂量、时间依赖性，且对细胞增殖抑制较低。

英文摘要：

L929 cells are used to study the effects of Magnetic Nano-Particles （MNPs） on cytotoxicity and evaluate the biological safety. MTT colorimetric assay was used to study the effects of different doses and durations of MNPs on the cells, and to evaluate the toxic effects of MNPs on cells and bio-safety. The results show that the leaching liquor with the MNPs modified with APTS is mainly of the first and the second grades well within the standard of cytotoxicity, but that of the MNPs modified by DMAB for 48h reaches the level of the fourth grade with a fair cytotoxicity. Compared with DMAB modified MNPs, the research in vitro reveals that the APTS modified MNPs have fewer inhibitions on the cell survival rate. Different doses and durations of MNPs see some differences in their effects on cytotoxicity, a certain dose may be found for MNPs with time-dependent lower inhibition of cell proliferation.