Glycerol-regulated facile synthesis and targeted cell imaging of highly luminescent Ag2Te quantum dots with tunable near-infrared emission

• Highly luminescent Ag2Te quantum dots (QDs) were prepared using glycerol as viscous solvent.
• Ag2Te QDs exhibited tunable near-infrared photoluminescence (PL) emission and high PL quantum yields.
• The QDs were favorably used for targeted PL imaging of tumor cells.

In this work, highly luminescent and emission tunable Ag2Te quantum dots (QDs) were facilely prepared by using water-dispersed glycerol as viscous solvent and CH3COOAg/Na2TeO3 as Ag/Te precursors. Viscous glycerol was utilized to slow the nucleation and growth of QDs at 200 °C, and enabled the isolation of QDs with different emission wavelengths. Experimental results revealed that the as-prepared Ag2Te QDs exhibited tunable near-infrared emission from 930 to 1084 nm, high photoluminescence (PL) quantum yields (QYs, more than 20%), good photostability and low cytotoxicity. After surface coating of a thin silica shell (∼1.4 nm), the resulting NH2 terminated Ag2Te@SiO2-NH2 displayed enhanced PL QYs, higher photostability and biocompatibility when compared with the original Ag2Te QDs. Through a facile carboxy-amine coupling, folic acid (FA) was grafted with Ag2Te@SiO2-NH2 to form Ag2Te@SiO2-FA nanocomposites, which were used for targeted PL imaging of folate receptor over-expressed tumor cells.

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