Laboratoire de Photonique Quantique et Moleculaire, Ecole Normale Superieure de Cachan and CNRS UMR 8537, Cachan, France.
ACS Nano. 2009 Dec 22;3(12):3955-62. doi: 10.1021/nn901014j.
Diamond nanoparticles (nanodiamonds) have been recently proposed as new labels for cellular imaging. For small nanodiamonds (size <40 nm), resonant laser scattering and Raman scattering cross sections are too small to allow single nanoparticle observation. Nanodiamonds can, however, be rendered photoluminescent with a perfect photostability at room temperature. Such a remarkable property allows easier single-particle tracking over long time scales. In this work, we use photoluminescent nanodiamonds of size <50 nm for intracellular labeling and investigate the mechanism of their uptake by living cells. By blocking selectively different uptake processes, we show that nanodiamonds enter cells mainly by endocytosis, and converging data indicate that it is clathrin-mediated. We also examine nanodiamond intracellular localization in endocytic vesicles using immunofluorescence and transmission electron microscopy. We find a high degree of colocalization between vesicles and the biggest nanoparticles or aggregates, while the smallest particles appear free in the cytosol. Our results pave the way for the use of photoluminescent nanodiamonds in targeted intracellular labeling or biomolecule delivery.
金刚石纳米粒子（纳米金刚石）最近被提议作为细胞成像的新标记物。对于小的纳米金刚石（尺寸 <40nm），共振激光散射和拉曼散射截面太小，无法进行单个纳米粒子的观察。然而，纳米金刚石可以通过室温下完美的光稳定性来实现光致发光。这种显著的特性使得在长时间尺度上更容易进行单个粒子的跟踪。在这项工作中，我们使用尺寸 <50nm 的发磷光纳米金刚石进行细胞内标记，并研究了它们被活细胞摄取的机制。通过有选择性地阻断不同的摄取过程，我们表明纳米金刚石主要通过内吞作用进入细胞，并且汇集的数据表明它是网格蛋白介导的。我们还使用免疫荧光和透射电子显微镜检查了纳米金刚石在胞内的内体定位。我们发现囊泡与最大的纳米颗粒或聚集体之间具有高度的共定位，而最小的颗粒则在细胞质中自由存在。我们的结果为发磷光纳米金刚石在靶向细胞内标记或生物分子传递中的应用铺平了道路。
