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A Cyanine-Modified Nanosystem for in Vivo Upconversion Luminescence Bioimaging of Methylmercury

2013; American Chemical Society; Volume: 135; Issue: 26 Linguagem: Inglês

10.1021/ja403798m

1943-2984

Yi Liu, Min Chen, Tianye Cao, Yun Sun, Chunyan Li, Qian Liu, Tianshe Yang, Liming Yao, Wei Feng, Fuyou Li,

Mercury impact and mitigation studies

Methylmercury (MeHg(+)) is a strong liposoluble ion, which can be accumulated in the organs of animals and can cause prenatal nervous system and visceral damage. Therefore, the efficient and sensitive monitoring of MeHg(+) in organisms is of great importance. Upconversion luminescence (UCL) detection based on rare-earth upconversion nanophosphors (UCNPs) as probes has been proved to exhibit a large anti-Stokes shift, no autofluorescence from biological samples, a remarkably deep penetration depth, and no photobleaching. In this study, a hydrophobic heptamethine cyanine dye (hCy7) modified by two long alkyl moieties and amphiphilic polymer (P-PEG)-modified nanophosphors (hCy7-UCNPs) was fabricated as a highly sensitive water-soluble probe for UCL monitoring and bioimaging of MeHg(+). Further application of hCy7-UCNPs for sensing MeHg(+) was confirmed by an optical titration experiment and upconversion luminescence live cell imaging. Using the ratiometric upconversion luminescence as a detection signal, which provides a built-in correction for environmental effects, the detection limit of MeHg(+) for this nanosystem was as low as 0.18 ppb. Importantly, the hCy7-UCNPs nanosystem was shown to be capable of monitoring MeHg(+)ex vivo and in vivo by upconversion luminescence bioimaging.