Fraunhofer Institute for Ceramic Technologies and Systems, Dresden, Germany.
Inhal Toxicol. 2009 Jul;21 Suppl 1:35-9. doi: 10.1080/08958370902942608.
Toxicological investigations on nanoparticles require a comprehensive physico-chemical characterization to get useful information about the powder as well as the behavior of the suspended nanoparticles in water and physiological media. Therefore, we characterized the often used TiO(2) P25 and developed procedures to get stable, homogeneous, and well-defined nanoparticle suspensions. A titration of the zeta potential as a function of the pH yielded the conclusion that the TiO(2) suspension is stable at a pH of 4 or lower. In this region the zeta potential is higher than 30 mV, which guarantees a high stability of the suspended particles. Hence, a stable TiO(2) initial suspension was prepared in 0.1 mM HCl having a mean particle size of 170 +/- 5 nm, which was determined by dynamic light scattering. Furthermore, the initial suspension was added to different physiological media (0.9% NaCl solution, phosphate-buffered saline [PBS], Hanks balanced salt solution [HBSS], Dulbecco's modified Eagle's medium [DMEM]) for studying the agglomeration behavior. As a result, the agglomeration kinetics at the same TiO(2) concentration is independent of the used media. Investigations with PBS containing bovine serum albumin (BSA) and DMEM supplemented with 10% FBS revealed that these protein additions inhibit the agglomeration of the particles. Thus, the physiological media contains particles that are stabilized through the steric or electrosteric effect of BSA and of the proteins in FBS, respectively. Consequently, the particles keep their size from the initial suspension. Finally, our procedure demonstrated on TiO(2) P25 results in homogeneously suspended particles in physiological media. This definite status of the particles means an improvement for toxicological testing and understanding.
纳米颗粒的毒理学研究需要全面的物理化学特性描述，以获得有关粉末以及悬浮纳米颗粒在水中和生理介质中行为的有用信息。因此，我们对常用的 TiO(2) P25 进行了特性描述，并开发了制备稳定、均匀和明确的纳米颗粒悬浮液的方法。通过对 pH 值的zeta 电位滴定，可以得出结论，TiO(2)悬浮液在 pH 值为 4 或更低时是稳定的。在这个区域，zeta 电位高于 30 mV，这保证了悬浮颗粒的高稳定性。因此，在 0.1 mM HCl 中制备了稳定的 TiO(2)初始悬浮液，其平均粒径为 170 +/- 5 nm，这是通过动态光散射法确定的。此外，将初始悬浮液添加到不同的生理介质（0.9% NaCl 溶液、磷酸盐缓冲盐水[PBS]、汉克平衡盐溶液[HBSS]、杜尔贝科改良伊格尔培养基[DMEM]）中，以研究团聚行为。结果表明，在相同的 TiO(2)浓度下，团聚动力学与所使用的介质无关。用含有牛血清白蛋白（BSA）的 PBS 和补充有 10% FBS 的 DMEM 进行的研究表明，这些蛋白质的添加抑制了颗粒的团聚。因此，生理介质中含有通过 BSA 的空间位阻或电动位阻效应稳定的颗粒，以及 FBS 中的蛋白质稳定的颗粒。因此，颗粒保持了初始悬浮液中的大小。最后，我们的方法在 TiO(2) P25 上的结果表明，在生理介质中得到了均匀悬浮的颗粒。颗粒的这种明确状态意味着在毒理学测试和理解方面得到了改善。
