In vivo fate of Ag2Te quantum dot and comparison with other NIR-II silver chalcogenide quantum dots

Narrow bandgap Ag 2 Te quantum dot (QDs) hold great promise in the fields of bioimaging, chemo-/bio-detection, and thermoelectric materials, but their biosafety has not been well estimated yet. In this study, we studied the biodistribution and toxicity of polyethylene glycol–coated Ag 2 Te QDs (Ag 2 Te QDs-PEG) in mice after a single intravenous injection. After entering the mice, Ag 2 Te QDs-PEG displayed a short circulation time in the blood (half-life was less than 2 h), and mainly accumulated in the liver and spleen. The stability of Ag 2 Te QDs-PEG in the mice depended on accumulation organ and time. Ag 2 Te QDs-PEG were stable in the spleen within 28 days but decomposed in the liver after 7 days. The decomposed Ag 2 Te QDs-PEG were eliminated from the body via different routes, as Ag was detected only in feces while Te was found only in urine. Meanwhile, Ag 2 Te QDs-PEG did not show obvious adverse effects on the body weights, organ indices, biochemical parameters, the levels of essential metal Cu and Zn in organs, and organ pathological investigations during 28 days. In addition, the important effects of anion to the fates of silver chalcogenide QDs in vivo was demonstrated by comparing the distributions of the Ag 2 Te QDs and other two silver chalcogenide QDs (Ag 2 S and Ag 2 Se). Our findings indicate Ag 2 Te QDs have good biocompatibility in mice, which is a guarantee for their safe applications in the future.