Uptake of Ultrasmall Fluorescent Gold Nanoclusters by Live Hela Cells

Abstract

The development of advanced fluorescence-based imaging techniques in the life sciences depends in significantly on the further development of specific fluorescence markers. Gold nanoclusters (AuNCs) are a novel type of nanomaterials which have attracted great interest in recent years. Composed of only a few atoms, AuNCs exhibit bright tunable fluorescence ranging from the visible to the infrared. Owing to their ultrasmall size, good photophysical properties and low cytotoxicity, fluorescent AuNCs have been recognized as promising probes for live cell labeling and intracellular sensing [1,2]. Still, little is known about the interactions of AuNCs with biological systems. Here we have studied the uptake behavior of water-soluble fluorescent AuNCs by live HeLa cells using confocal fluorescence microscopy. Unlike larger particles, ultrasmall AuNCs accumulate at the plasma membrane before they are internalized and become enwrapped in endosomes and, subsequently, lysosomes. We have also explored the endocytic mechanisms by which AuNCs are internalized by using specific inhibitors.[1]Shang, L.; Dong, S.; Nienhaus, G. U., Nano Today 2011, 6 (4), 401-418.[2]Shang, L.; Nienhaus, G. U., Biophys. Rev. 2012, DOI: 10.1007/s12551-012-0076-9.