Nuclear uptake of ultrasmall gold-doxorubicin conjugates imaged by fluorescence lifetime imaging microscopy (FLIM) and electron microscopy.
Nuclear uptake of ultrasmall gold-doxorubicin conjugates imaged by fluorescence lifetime imaging microscopy (FLIM) and electron microscopy.
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荧光寿命成像显微镜（FLIM）已被用于图像自由和封装的阿霉素（Dox）摄取到细胞中，因为Dox与DNA的相互作用导致的特征寿命的变化。然而，没有一个报道的Dox缀合物能够进入细胞核。在这项工作中，我们使用FLIM显示核摄取的2.7 nm平均直径的Au纳米粒子共轭Dox。标记模式与游离Dox所见的显著不同，在所有时间点均具有较慢的核进入和较强的细胞质标记。随着细胞死亡，标记的模式随着细胞内结构的解体而进一步改变，这与Au-Dox与膜的结合一致。Au的分布和细胞内结构的变化的模式，证实了使用电子显微镜，并表明不同的机制与稳定的Au-Dox缀合物相比，单独的Dox的细胞毒性。此类缀合物是用于克服Dox抗性癌症中的抗性的有前景的工具。
Fluorescence lifetime imaging microscopy (FLIM) has been used to image free and encapsulated doxorubicin (Dox) uptake into cells, since interaction of Dox with DNA leads to a characteristic lifetime change. However, none of the reported Dox conjugates were able to enter cell nuclei. In this work, we use FLIM to show nuclear uptake of 2.7 nm mean diameter Au nanoparticles conjugated to Dox. The pattern of labelling differed substantially from what was seen with free Dox, with slower nuclear entry and stronger cytoplasmic labelling at all time points. As the cells died, the pattern of labelling changed further as intracellular structures disintegrated, consistent with association of Au-Dox to membranes. The patterns of Au distribution and intracellular structure changes were confirmed using electron microscopy, and indicate different mechanisms of cytotoxicity with stable Au-Dox conjugates compared to Dox alone. Such conjugates are promising tools for overcoming resistance in Dox-resistant cancers.