title: Possible gadolinium ions leaching and MR sensitivity over-estimation in mesoporous silica-coated upconversion nanocrystals.
abstract: Mesoporous silica (m-SiO2) coated gadolinium (Gd) ions-doped upconversion nanoparticles (UCNPs) are regarded as one of most attractive nano-platforms which hold great potential in future cancer theranostics. The current general synthetic strategy for such promising structures includes the extraction of surfactant molecules in the final step. Here, in this article, we focus our interest on probing the potential influence of hydrochloric acid extraction on lanthanide ions leakage, MR sensitivity over-estimation and the optical intensity weakening of m-SiO2 coated Gd-doped UCNPs. Control experiments provide evidence of inner core damage, Gd(3+) ion release and residual Gd(3+) ions "trapped" within the core@shell structures. Our investigation shows that: (1) the small Gd-doped UCNPs could be fragile and sensitive to the hydrochloric acid-extraction and thermal treatment processes; and (2) the presence of "trapped" Gd(3+) ions not only provokes the concerns of potential cytotoxicity but also interfere with the contrast imaging tests of Gd-doped UCNPs, providing possible erroneous information on the determination of the longitudinal relaxivities of given probes.
authors.affiliation: Department of Radiology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
authors.forename: Shengjian
authors.initials: S
authors.lastname: Zhang
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Jiang
authors.forename: XiaoHang
authors.initials: X
authors.lastname: Liu
authors.forename: Liangping
authors.initials: L
authors.lastname: Zhou
authors.forename: Weijun
authors.initials: W
authors.lastname: Peng
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D003287:Contrast Media / Q000737:chemistry / Q000633:toxicity; D005682:Gadolinium / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D007477:Ions / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D007477:Ions; D012822:Silicon Dioxide; D005682:Gadolinium