| Rare earths luminescence is one of the most prominent function oflanthanide-based compounds. Different arrangements of the lanthanide4f electronsgenerate various energy levels, which give rise to numerous absorption and emissionbands. The particular structure of lanthanide ions enables them emit numerous bandsof light involved from near infrared, visible to ultraviolet. The unique optical,electrical and magnetism properties of lanthanide-based materials endow theirpotential applications in photovltatics, photocatalytic, sensing, medical imaging anddiagnosis.Recently, the quest for diagnostics and therapeutics of enhance performancesspurred greater research efforts above the synthesis and properties of materials. Withwell-defined physicochenmical properties such as size, shape, composition andsurface chemistry, nanomaterials can be engineered with specially designedfunctionalities. The resulting nanosystems are capable of simultaneous detection,diagnosis and treatment of disease.Based on the above obtained conclusion, this thesis presents a systematicresearch focused on the multifunctional lanthanide-based compounds—synthesis andpotential applications:(1) The Y(OH)CO3H2O were synthesized via a general urea-based homogeneousprecipitation. Then the silica was homogeneously coated around Y(OH)CO3H2Omicrospheres by a modified St ber method. The formed Y(OH)CO3@SiO2particleswere used as a sacrificed template, which not only acts as the morphologicalcontroller, but also as the reactant source of Y3+for the formation of cubic-phased (α-)NaYF4. Possible reaction mechanism was explored in terms of a surface-protectedetching and ion-exchange reaction process. To explore their application potential, thestorage and release behavior of Rhodamine640dye in the porous α-NaYF4microspheres was investigated, showing a relatively high loading efficiency and asustained release ratio. Under near-infrared (NIR) irradiation, porous α-NaYF4microspheres doped with lanthanide ions showed typical upconverting luminescence characteristics. The above features and properties indicate that our present porousupconverting luminescence particles are promising in biological applications asluminescence imaging agents and drug carriers.(2) Herein, we developed a novel fluorescent probe for H2O2sensing, CePO4:Tbcolloidal solution, which were synthesized via a facial wet-chemical method. Uponthe addition of H2O2, the luminescence of colloidal CePO4:Tb solution respondslinearly in a wide H2O2concentration range of0–200μM, allowing for quantitativedetection of H2O2. This sensing material for H2O2is also suitable for the detection ofglucose since H2O2is generated via the catalytic oxidation of glucose by the oxidaseenzymes. The fluorescence response of CePO4:Tb solution to H2O2and glucose israpid and concentration dependent. The F0/F vs.[Q] can be well fitted usingStern-Volmer equation in a wide analyte concentration range with the Ksv quenchingconstant of13700M1and14450M-1, respectively. Except for a wide linear response,a low detection limit and a high reproducibility, our present method for glucosesensing show a highly specific response to glucose in the mixed carbohydrate solutiondue to the specificity of glucose oxidase to glucose. This lanthanide-based fluorescentsensing material might be potential for detecting H2O2and glucose in biologicalapplications. |
