title: Preparation and characterization of ZnS:Tb,Gd and ZnS:Er,Yb,Gd nanoparticles for bimodal magnetic-fluorescent imaging.
abstract: As bimodal magnetic-fluorescent imaging agents, the preparation of ZnS:Tb,Gd and ZnS:Er,Yb,Gd nanoparticles via a facile homogeneous precipitation method is reported. The results show that these nanoparticles are almost spherical in shape with a diameter of 100-200 nm approximately and a major phase of wurtzite-structured ZnS. The products can successfully label the human hepatocellular carcinoma (HepG2) cells and present low toxicity even at concentrations up to 5 mg mL(-1). Additionally, for the ZnS:Er,Yb,Gd nanoparticles calcinated above 950 °C, NIR-to-visible up-conversion fluorescence were obtained, which is believed to be superior to traditional ZnS-based bioimaging agents with down conversion. In MRI studies, they reveal a longitudinal relaxivity rate (r(1)) of 39.46 mM(-1) s(-1) and 57.8 mM(-1) s(-1), respectively, which are much larger than the conventional Gd-DTPA and currently reported Gd-base nanoparticles, suggesting great potential as MRI agents.
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Kezheng
authors.initials: K
authors.lastname: Chen
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry; D005063:Europium / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D005682:Gadolinium / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D018613:Microscopy, Confocal; D013440:Sulfides / Q000737:chemistry*; D015018:Ytterbium / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D005456:Fluorescent Dyes; D013440:Sulfides; D017967:Zinc Compounds; D005063:Europium; D005682:Gadolinium; C031238:zinc sulfide; D015018:Ytterbium