纳米SiO_2粒子特性及其在无细胞体系中氧化能力的检测及意义

Characterization and non cellular ROS activities of nano silica particles

目的:检测纳米SiO2粒子的特性及其在无细胞体系中的氧化能力,为医用纳米SiO2粒子体内外毒性的预测提供依据。方法:用透射电镜观测2种纳米SiO2粒子粒径、分散性、形状;用Zeta电位粒度分析仪检测纳米粒子在不同介质(纯水、生理盐水、10%Tween80溶液、RPMI1640培养液、含1%胎牛血清的RPMI1640细胞培养液,超声30s)溶液及不同时间(0、24、48和72h)的粒径分布及团聚状态;用DDCFH-DA法F检测粒子在无细胞体系中自发产生自由基的能力。结果:电镜结果显示,2种纳米SiO2粒子均呈球形,大小一致,分布均匀、分散性好,粒子平均粒径分别为(43.0±4.2)和(68.0±5.7)nm;在纯水、生理盐水、10%Tween80溶液、RPMI1640培养液及含1%胎牛血清的RPMI1640细胞培养液中,Si-43nm及Si-68nm粒子粒径变化很大,其中在生理盐水中的粒径最接近电镜结果,为74.0和96.7nm。超声30s后0、24、48和72h时,Si-43nm及Si-68nm粒子粒径在生理盐水中不发生团聚;在含1%胎牛血清的RPMI1640细胞培养液中发生团聚,形成相似大小的团聚体;在30～100μg的质量范围内,2种粒子自发产生自由基的能力相似但很弱,相当于2.5μmol.L-1左右H2O2当量。结论:一定粒径的纳米SiO2在细胞培养液中形成大粒径团聚体,粒子自身只有较弱的自发产生自由基的能力。

Objective To detect the characterization and non cellular ROS activities of nano silica particle and provide references for predicting its toxicity in vivo and in vitro. Methods Transmission electron microscope （TEM） was used to observe particle size, shape and dispersibility of the two silica particles; the size and agglomeration state of particles in water, saline, 10% Tween 80, RPMI 1640 and RPMI 1640 containing 1% FBS were measured in 0, 24, 48 and 72 h after 30 s-sonication by Zeta Potential Analyzer; non cellular ROS activity was detected using DCFH-DA regents. Results TEM image showed nano silica particles were round and dispersed evenly; the average sizes of the two silica particles were （43.0±4.2） and （68.0±5.7） nm. Silica particles had different sizes in water, saline, 10% Tween 80, RPMI 1640 and RPMI1 640 containing 1% FBS, among them, two particles had smallest sizes in saline, which were 74.0 and 96.7nm, respectively. And at 0, 24, 48 and 72 h after 30 s-sonication, Si-43nm and Si-68nm did not form agglomeration in water but formed similar agglomeration in RPMI 1640 cell culture medium containing 1% FBS. The two nanoparticles hardly caused any increasing of ROS between 30-100μg mass range in cell free system, just equivalent 2.5μmol·L^-1 H2O2. Conclusion Nano silica particles could form agglomerations in cell culture medium and almost have no ROS activities in non cellular system.