Friedrich-Loeffler-Institut Mariensee, Institute of Farm Animal Genetics, Federal Research Institute of Animal Health, Holtystr. 10, D-31535 Neustadt, Germany.
J Biomed Opt. 2010 May-Jun;15(3):036015. doi: 10.1117/1.3461170.
Gold nanoparticles (AuNPs) have the potential to become a versatile biomarker. For further use of AuNPs labeled with functionalized molecules, their visualization in biological systems by routine laboratory tools such as light microscopy is crucial. However, the size far below the diffraction limit affords specialized parameters for microscopical detection, which stimulated the current study, aimed to determine from which size onward AuNPs, either in dispersion or cell-associated, can be reliably detected by standard confocal microscopy. First, gold colloids of size-restricted fractions are examined in dispersion. At a minimum particle size of 60 nm, detection appears to be reliable. Particle counts in dilution series confirm these results by revealing single particle detection of 60-nm colloids. Second, AuNPs are visualized and quantified in cells, which interestingly cause a phase shift in the reflection of AuNPs. Gold mass spectroscopy confirms the number of AuNPs counted microscopically inside cells. Furthermore, it demonstrates for the first time a very high diffusion rate of 15-nm particles into the cells. In conclusion, the results back the suitability of confocal microscopy for the quantitative tracking of colloidal and intracellular gold nanoparticles sized 60 nm.
金纳米粒子（AuNPs）具有成为多功能生物标志物的潜力。为了进一步使用功能化分子标记的 AuNPs，通过常规实验室工具（如荧光显微镜）在生物系统中对其进行可视化至关重要。然而，尺寸远低于衍射极限为显微镜检测提供了专门的参数，这激发了当前的研究，旨在确定从哪个尺寸开始，无论是分散的还是与细胞相关的 AuNPs，都可以通过标准共聚焦显微镜可靠地检测到。首先，在分散体中检查尺寸受限分数的金胶体。最小粒径为 60nm 时，检测似乎是可靠的。稀释系列中的粒子计数通过揭示 60nm 胶体的单粒子检测进一步证实了这些结果。其次，在细胞中可视化和定量 AuNPs，有趣的是，这会导致 AuNPs 反射的相移。金质谱证实了在细胞内显微镜下计数的 AuNPs 的数量。此外，它首次证明了 15nm 颗粒非常高的扩散率进入细胞。总之，这些结果支持共聚焦显微镜用于对 60nm 大小的胶体和细胞内金纳米粒子进行定量跟踪的适用性。
