Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63130, USA.
Nat Nanotechnol. 2011 Apr 24;6(6):385-91. doi: 10.1038/nnano.2011.58.
In vitro experiments typically measure the uptake of nanoparticles by exposing cells at the bottom of a culture plate to a suspension of nanoparticles, and it is generally assumed that this suspension is well-dispersed. However, nanoparticles can sediment, which means that the concentration of nanoparticles on the cell surface may be higher than the initial bulk concentration, and this could lead to increased uptake by cells. Here, we use upright and inverted cell culture configurations to show that cellular uptake of gold nanoparticles depends on the sedimentation and diffusion velocities of the nanoparticles and is independent of size, shape, density, surface coating and initial concentration of the nanoparticles. Generally, more nanoparticles are taken up in the upright configuration than in the inverted one, and nanoparticles with faster sedimentation rates showed greater differences in uptake between the two configurations. Our results suggest that sedimentation needs to be considered when performing in vitro studies for large and/or heavy nanoparticles.
体外实验通常通过将培养板底部的细胞暴露于纳米颗粒悬浮液中来测量纳米颗粒的摄取，并且通常假定该悬浮液是良好分散的。然而，纳米颗粒会沉降，这意味着细胞表面上的纳米颗粒浓度可能高于初始体相浓度，并且这可能导致细胞摄取增加。在这里，我们使用直立和倒置的细胞培养配置来表明金纳米颗粒的细胞摄取取决于纳米颗粒的沉降和扩散速度，并且与尺寸，形状，密度，表面涂层和纳米颗粒的初始浓度无关。通常，在直立配置中摄取的纳米颗粒比在倒置配置中多，并且沉降速率较快的纳米颗粒在两种配置之间的摄取差异更大。我们的结果表明，在进行大颗粒和/或重颗粒的体外研究时，需要考虑沉降。
