title: A cyanine-modified nanosystem for in vivo upconversion luminescence bioimaging of methylmercury.
abstract: 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.
authors.affiliation: Department of Chemistry and The State Key Laboratory of Molecular Engineering of Polymers and Institute of Biomedicine Science, Fudan University, Shanghai, 200433, P. R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Tianye
authors.initials: T
authors.lastname: Cao
authors.forename: Yun
authors.initials: Y
authors.lastname: Sun
authors.forename: Chunyan
authors.initials: C
authors.lastname: Li
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Tianshe
authors.initials: T
authors.lastname: Yang
authors.forename: Liming
authors.initials: L
authors.lastname: Yao
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.forename: Fuyou
authors.initials: F
authors.lastname: Li
mesh_terms: D000818:Animals; D002232:Carbocyanines / Q000008:administration & dosage / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D049449:Luminescence; D008163:Luminescent Measurements; D008297:Male; D008767:Methylmercury Compounds / Q000032:analysis*; D051379:Mice; D008815:Mice, Inbred Strains; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D010316:Particle Size; D013499:Surface Properties
chemical_list: D002232:Carbocyanines; D008767:Methylmercury Compounds