Purine-stabilized green fluorescent gold nanoclusters for cell nuclei imaging applications.

We report facile one-pot synthesis of water-soluble green fluorescent gold nanoclusters (AuNCs), capped with 8-mercapto-9-propyladenine. The synthesized AuNCs were characterized by Fourier transform infrared (FTIR), powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), (1)H NMR, and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. These nanoclusters show high photostability and biocompatibility. We observed that AuNCs stain cell nuclei with high specificity, where the mechanism of AuNC uptake was established through pathway-specific uptake inhibitors. These studies revealed that cell internalization of AuNCs occurs via a macropinocytosis pathway.