One-pot aqueous synthesis of germanium-doped cadmium sulfide quantum dots as fluorescent probes for cell imaging

Water-soluble germanium-doped cadmium sulfide quantum dots (Ge:CdS q-dots) were successfully synthesized by a facile one-pot method, and used as fluorescent probes for labeling live MCF-7 cells. The optical properties of the q-dots and several key parameters of the synthesis conditions were studied, and the mechanism of these parameters was also discussed. After doping with germanium, the PL intensity increased 50%, while improving the photostability and fluorescence quantum yield. Furthermore, the toxicity of CdS quantum dot decreased after doping with germanium due to its low toxicity, which greatly improved the CdS quantum dots biocompatibility. Then the doped quantum dots modified with folic acid (FA) to use as fluorescent probes, which expanded the application of semiconductor quantum dots in the biomedical field.