In vivo fate of Ag 2 Te quantum dot and comparison with other NIR-II silver chalcogenide quantum dots

Narrow bandgap Ag2Te 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 Ag2Te QDs (Ag2Te QDs-PEG) in mice after a single intravenous injection. After entering the mice, Ag2Te 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 Ag2Te QDs-PEG in the mice depended on accumulation organ and time. Ag2Te QDs-PEG were stable in the spleen within 28 days but decomposed in the liver after 7 days. The decomposed Ag2Te 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, Ag2Te 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 Ag2Te QDs and other two silver chalcogenide QDs (Ag2S and Ag2Se). Our findings indicate Ag2Te QDs have good biocompatibility in mice, which is a guarantee for their safe applications in the future.